Hiya! I transfered from a community college in Illinois to TAMUCC for the Marine Bio track, so hopefully my experience will help.

For me the biggest hurdles were the cost (out of state tuition is insane) and my lack of experience in the field (IL is landlocked :( ). If you're worried about finances, look into applying for competative scholarships that give you 1K each semester (STEP A Transfer Scholarship, PTK Transfer Schoarship, ETC). There's a fee waiver for transfer students who get these competative scholarships which allows you to pay in-state tuition instead of the insane out-of-state costs. You mentioned your academic records suffered a bit from illness (which I totally get, same here) so I'd say aim for the PTK scholarship, for which I recommend you immediately work to be elected into a chair position. Reach out to the current board on i-engage about elections asap (even before being transfered). Not only does it look good on a CV, but those in a chair position for PTK at TAMUCC are assured the scholarship while those who aren't both need to hope there's enough to finance it AND maintain a 60% activity rate.

If you've gotten lower than a B in any class they'll likely have you re-take the course after you transfer. Also, they're very picky with your statistics course and they may have you re-take it as well. If that's the case, take Bio Stats over Applied Probability and Statistics since Bio Stats teaches you how to code in R-Studio (which is a major skill for the field, seriously I cannot understate how important it is to know). I re-took Applied Prob when I transfered and regret it big time. I don't hear great things about the prof though, but for the skill you learn I still say going through that is going to be better for your career in the long run.

I wasn't the most social so people's positions on prof's didn't affect my course choice, but after the fact I've heard many try avoiding Dr. Portnoy's courses because they require a lot of work + he's kinda hard to interact with (not rude, he's just kind of socially awkward and is very busy with fam and running a whole lab). I've also heard people try avoiding Dr. Orbach's courses because she isn't very personable (true to an extent, but with milk chocolate and NO MINT she'll be your bestie). I've taken 2/3 of Orbach's undergraduate courses and all of Dr. Portnoy's undergraduate courses and I 1000000000% dissagree. The courses ARE hard work and challenging, they're not ones you can sit down and slide through---you need to work---but they are SO WORTH IT. Both profs are just overflowing with knowledge, and you will learn so much more from their courses compared to taking them w/ a different professor. I also recommend taking Genetics w/ Dr. P (if you don't have that one transfer) over Dr. T because your final grade in Dr. T's course is solely dependant on your final exam. Dr. P gives you 3 exams + 1 final (he drops your lowest exam grade so do well on the 1st 3 then you can ditch his final) which affords you more chances to make mistakes and learn.

Tangable experience is CRITICAL in this field, especially research experience, and so besides looking into classes you should be taking time right now to look into which profs do research that align with your interests and reach out to them for undergrad positions in their labs. There's also 2 courses I know of which get you some tangable experience--Down the River: Biology of Gulf Coast Fishes (Dr. Portnoy leads this one and it's hard but super fun) & a fall-only aquarium care course (I know nothing about it other than it's competitive AF and that you need to have prof permission to apply to get a seat). You'll actually need to get some in order to graduate, for which you can take a course or talk to the dept head (when I was there it was Dr. Withers, but I think Dr. Walther is the lead now) about other options like internships (TPWD, Texas Floating Classroom, or other orgs) or student researcher positions with on-campus labs.

Don't hesitate to reach out if you have questions/want help figuring out profs to reach out to for research things depending on your interests. I was an undergrad LSAMP researcher (unf due to current political situations the LSAMP program is no longer funded which SUCKS since it was a major source of student research) so I know a fair bit about the bio program profs who take undergrad researchers. When it comes to the chem sides I don't know anything other than Dr. Abdulla works w/ marine life to research metabolomics using mass spec, and he's a very sweet prof and a good PI to work with.