Congrats on your accomplishments! If your “worst case scenario” is UMass Amherst, you’re in great shape!
Have you run the Net Price Calculators for all of these schools? I’m unclear on how you could possibly pay for UT Austin as an out of state student. The other three OOS publics on your list do have need-based aid for OOS students (only for very low income at UMich so make sure you qualify), but it behooves you to run the numbers and make sure they would even work. USC meets need but I have seen many low-income students express shock at how stingy their aid packages turned out to be in comparison to other schools, so definitely do your research on whether it would be affordable for you.
There’s a wide range of transfer acceptance rates on this list. These schools may also vary in terms of being need-blind or need-aware for transfer students. Make sure you know what you’re dealing with at each school, specifically with regard to transfer admissions. (And understand that the OOS transfer acceptance rates will be much lower at UMich, UVA, UNC, and even Cornell.)
For the schools that are the biggest long shots, waiting another year will make more sense. If there are some that you only marginally prefer over UMass but are just hoping to accomplish the transfer sooner, go ahead and shoot your shot and see what happens. For example, maybe it’s worth giving Northeastern a try - the better to get into the co-op pipeline earlier - even though getting in as a sophomore might be hard.
Have you considered Emory? They do not consider freshman grades, so your HS transcript wouldn’t be as much of a liability - maybe a good need-met school to try for a sophomore-transfer.
How about Babson? They might really love your entrepreneurial record, and you might really enjoy their approach to business education. Excellent school that meets need… and they take both fall and spring transfers, so you could also compromise and apply in the fall for sophomore spring.