Well…first of all…take Princeton off of your list. The school hasn’t accepted transfer students in years.
Your aid at the early college might not be affected by your sister’s enrollment. I don’t think either of those schools guarantees to meet all the need of all accepted students. So…you might not get sufficient aid to attend.
Remember, the vast majority of colleges do NOT meet full need for all accepted students. HYSM meet need for transfers, but some schools that meet full need for incoming freshmen do not do so for transfers.
The other thing…acceptances to HYMS and the like are in the single digits for incoming freshmen. Their acceptance rates for transfers are VERY VERY low…single digits. In other words, most who apply to transfer to these schools do not get accepted.
If you are looking for the best potential for need based and merit aid awards, your best bets are as an incoming freshman, not a transfer student.
Is there some reason why you aren’t applying to four year schools early? Is there one reason why you feel you must graduate from HS early?
I think if finances are important, you need to examine your decisions very carefully.