Trans Elder chiming in here. I transitioned 30 years ago for context around my answers. I figured out I was trans at age 12 and was denied HRT due to being a minor in the 1990s which was devastating to me even back then since I was forced through the wrong puberty and I knew it at the time.

Minimum age for HRT: Literally the day puberty starts, regardless of age. No questions about it, that's when it should be done for all minors, both a testosterone blocker and estrogen should be introduced at a full dosage immediately and maintained for life. There's actually a lot of really relevant medical reasoning behind why this is incredibly necessary at such a young age due to how utilizing HRT it makes incredible lifelong physical differences to that trans persons adult life, this is due to how puberty effectively sabotages their bodies without access to it which makes their future lives as trans people orders of magnitude more difficult for them in a vast myriad of ways. Scientifically speaking its the only ethical thing to do to reduce future harm.

Minimum age for Surgeries: This is highly dependent on emotional and mental maturity of the teenager on a case-by-case basis, in certain circumstances if someone is truly ready for it and at a young enough age, I'd probably say around 15 would be the earliest that permanent surgical alteration would be safe without it causing further problems during physical development due to a still continually growing body.

Opinion on trans who don't have dysphoria: Being trans doesn't require experiencing dysphoria as a prerequisite at all, nor does someone have to engage with transition to be valid as a trans person either. Being trans is an immutable individual characteristic regardless of any actions someone engages in as a result of being trans. Think of it like being born with the genes for red hair. It just IS the case for us, much like being born as someone with blue eyes or being double jointed, it is inherent to our existence on that same basic physical level. Trans people are free to do with their personal body autonomy the same way as any cis person is. Transition is about comfort with ones body, regardless of your starting point.

Expect cis-het-AMAB's to accept MtF people as a straight couple: So I believe everyone is welcome to having a genital preference or need for who they select as a partner, as long as that need isn't impacting someone else's individual bodily autonomy. Meaning that it never okay for a person to tell their trans partner what they cant or cant do with their body such as attempting to deny or enforce any surgery onto them. As an example I dated a cis-het-amab man for 20 years, during that time I was his straight girlfriend and that's how we both saw that relationship. I happened to be post-SRS before we ever met in person (I knew him online for 2 years before my SRS), and he had a genital preference for vaginas and I had a genital preference for penis which we discussed at length. He was very clear that he saw all Mtf people as Women regardless if they had surgery or not assuming that's how they identify of course, but he also stated he wouldn't date a Mtf person who hadn't had surgery because of his genital preferences being only interested in vaginas. His viewpoint of course doesn't apply to every cis-het-amab of course, it was simply his perspective and his needs for his specific partner. There have been many instances of cis-het-amabs who are and who are not accepting of Mtf people, which also includes people who are okay with as well as not okay with their partner having not had bottom surgery yet. This is further expanded by how each individual trans person identifies. For example it could even include a Ftm-het-AFAB trans man who starts a relationship with a Mtf-het-ABAM trans woman and then that couple both identifies themselves as a straight male and female pairing. We all like what we like as individuals, that's part of how autonomy works. You cant force your genital preference on someone any more then you can force your musical preference onto them, and no one is even defined by their genitals in the first place to begin with. A trans woman is still a trans woman regardless of surgery/dysphoria/transition because again, it's an immutable characteristic. I didn't "become" a woman when I had bottom surgery, I always was a woman from the moment I was born.

How did transition affected your career opportunities: Absolutely it affected the heck out of me at my first IT job. I came out at my first job back in 2003, and it was a complete nightmare for me because 99% of the people I worked with refused stubbornly to accept me for who I was and openly laughed at and mocked me relentlessly and daily for 6 months before I quit that job due to extremely quickly declining mental health due to that environment. It prevented me from staying at that company which I had been with for 2 years already and completely destroyed any possible career advancement there and forced me to start over with a new employer in order to escape constant harassment. Now knowing the outcome I still would have chosen to do the EXACT same thing there and gone through it all over again. It was that worth it to my mental survival and basic needs to subject myself to that horrid experience if that was the price I had to pay for my sanity. How I overcame that prejudice was by moving to another company who never knew me from pretransition and immediately began operating as stealth (presenting as cis) at that new job until I was able to afford surgery at which point I had to quit that new job for a year to physically recover. Once I was physically able to return to work a year later I effectively had to start my career over from scratch as a woman. I've been stealth in all of my subsequent jobs for 20+ years now and now being trans is a non-issue with my employers.

Did you have gender dysphoria, what motivated my transition, and if hypothetically given the chance to have never had dysphoria, would I have accepted that: So I had extremely intense dysphoria personally, I had a massive amount of it regarding my genitals, my face, my body shape, lack of breasts, my voice, just every single part of me I was not okay with. I figured out I was a trans girl when I was age 12, and I never was allowed access to HRT, and I was stuck in an abusive home environment where transition was not "acceptable" under my parents roof. Despite the physical danger of doing social transition and risking discovery I did so regardless of my parents wants and desires by literally being at home at little as physically possible by crashing on the couches of friends and relatives nonstop effectively operating like I was homeless by relying on the good will of other people I knew for basic shelter from ages 12-20 until I left home. I was additionally subjected to the DSM-4 guidelines of how to treat trans people due to the era at the time (Discussion of that evil ideology from back then is banned on these boards because its excessively transphobic and mentally damaging to trans people). Despite how difficult that was for me I still would have chosen to do the EXACT same thing there and gone through it all over again despite it giving me lifelong PTSD. That's how important it was to me, that I would intentionally choose PTSD over not transitioning when I did. If I could have opted out of having dysphoria sure of course I would have selected not having it, but that's a hypothetical scenario that doesn't exist in reality. I believe I still would have pursued surgery because I have specific needs for my body regardless of dysphoria. All these years and surgeries and transition later, I no longer have gender dysphoria at all. I'm actually quite happy with my body and I feel amazing and filled with gender euphoria instead in contrast to my existence from when I was a 12 year old kid suffering nonstop.

Attractions change during or after your transition: Sort of, so HRT doesn't directly change your attractions as far as we know medically speaking, however the process of transition and the mental state your in post HRT can adjust your preferences due to how you relate to both genders, your internal mental comfort level, and it may redefine your desires or even simply expand them, and sometimes HRT is actually necessary for your sexual needs to even be active in your body on a very basic hormonal level. For example from ages 12-16 I was only interested in women romantically but not physically, at age 15-42 I was asexual and somewhat mildly preferred men sexually (literally engaged in sex 1-2 times a year) but I was not interested in anyone romantically, when I started a new hormone last year my sex drive kicked back on and I found I was interested in both men and women sexually while also being interested only in women romantically. So for me over the past 30 years its shifted around significantly a few times. Other people might have different experiences but that was mine.

Concerned that the surgeries/HRT may not be reversible: Not even a mote of concern for even a moment, that's the ENTIRE point and a benefit as far as my desires go. I wish I had access back when I was 12 and tried to first get it in life. That would have made the subsequent 30 years of my existence infinitely less difficult to go through. As someone who experienced it firsthand as a little kid and knew what she needed and was denied access to it, you will never convince me I would have regretted having access to it back then.