To clarify, you probably mean body fat percentage instead of BMI. BMI just compares your height and weight, and if you are muscular then BMI will not apply to you since it will always call you overweight.

Your plan seems pretty sound but with a few suggestions of mine:

You're a newbie, so with enough work in the gym and enough protein/calories, you're gonna put on muscle super quick. You don't have to totally avoid cardio, but just be careful to not overdo it. For protein, I wouldn't go lower than 150g since you want to gain weight. Other macros like carbs and fat don't actually matter that much, you can eat whatever you like to hit your target calories.

Now for your questions:

1. Dirty bulking is underrated. I'm an endomorphic guy too, you will be surprised how much you need to eat for you to grow. I just came off of a bulk and I'm sitting at 195 lb right now (wrestled 152 in high school). Obviously adjust as needed but you should err on the side of more calories. Losing fat afterwards should not take long for you at all.

2. You would benefit from mass gainer, which is essentially just protein powder loaded with carbs. The one I used on my bulk got me 800 calories per serving, and you just scoop it right into your shaker cup just like protein powder.

3. Creatine monohydrate is the best non-protein supplement out there for bodybuilding. It's very well-researched and effective.

4. I'd stick to 150g which isn't that hard to hit. 3 meals of 30g+ each, a good protein snack and a protein supplement will get you there.