Thought as much. Your “main reason” for transferring smacks of somebody legitimizing a desire to move ‘up’. As it happens, II think that’s. a perfectly fair and understandable desire. I just prefer it when a student owns it 
You have a LOT of ECs, but I think they are over-written. Obviously some of them must be bigger deals than others, but it is hard to tell which is which. Also, applying as an entering Junior you will want to consolidate down your HS ECs a lot- but that can wait until January, when you are actually applying.
Vandy has built a rep for being transfer-friendly, but Columbia- esp for a Jr! is not. I also wonder what (besides perceived prestige) is bringing this group together. Vandy in particular is an outlier. Your list is sort of the ones missing from last time, and no more cohesive (in any dimension that I can see). I think you still have work to do in figuring out what you really want, and what you have learned from (most of) a year at USC.
You turned down a lot of schools last year that seem just as likely- did you think of asking any of them about accepting the place now? (at least some of those schools say up front that they will keep your file for a year in case you change your mind)
The challenge, of course, will be getting aid that matches what you have.
(also, you thought NYU would be good for finaid?!)