I'll give you a bit of input on new programs in general (as I had interviewed at a newly opening program back in the day when I was applying to residency).
If you're into new stuff, this might be right up your alley. You'll likely have the opportunity to modify curriculum/rotations almost however you want. Since you'll be the first class of residents, they'll probably be trying to solicit feedback from you. They will also actually likely respond to this feedback and change major things because they'll want to optimize your rotations and want to keep you happy (cause they know if you talk bad about the program to new applicants next year, they're gonna be dead in the water recruitment-wise). However, expect some growing pains along the way. The nurses/other staff won't be used to having residents around and used to dealing directly with attendings, so might get easily frustrated with the multiple layers of communication, the "I need to check with my attending", the new batch of people every year who aren't used to the EMR or how to get home health or what you can/can't order from pharmacy or the 100 other little things you just learn about the system you're working in. Staff may try to leapfrog you directly to the attendings since that'll be likely easier for them.
If you want to be/stay in Florida, then obviously this would be a huge plus for you. Orlando is pretty nice too and pretty central in Florida. I do also share your concern though that there are 3 pediatric hospitals in Orlando alone (not to mention the somewhat nearby All Children's Hopkins hospital in Tampa), so I'd be asking about their volume/typical number of admit numbers and compare that to other hospitals you're looking at.
The faculty are good. Nemours was notorious over the past few years for aggressively going after good faculty at other institutions (and getting them). I know for a fact that at least a couple attendings on their list of residency program faculty are great.
You won't have senior residents which is going to be kind of weird for the first year. I suppose you'd work directly with attendings but things like nights/call are going to be interesting (but could be helpful and educational if you have easily reachable attendings and can be good for autonomy, which you don't tend to get a lot of in pediatrics, especially at bigger academic centers). Theres also just something different about asking other residents about what they'd typically do or how to handle different situations, etc. vs attendings. So again, you'd have to be very comfortable with brand new situations that nobody else has come across before (and nobody else may have an immediate solution to for you).
The concerns about residents being "not needed" are very valid concerns. Most new programs try to spin this as "we don't use you as workhorses, you'll have so much time for education" or say they're "educationally focused" instead of being "work focused". However, keep in mind that, as of right now, this hospital has been functioning perfectly fine without residents and would likely continue to function perfectly fine if you all up and left in the next year. That can be a plus and a minus. On the plus side you'll probably get less to do in terms of scutwork/social work (ex. probably won't have to set up followup appointments, get prior-auths, get OSH records, etc). On the minus side, there's something psychologically different when you know you're an essential part of the system (especially overnight). Residents at many programs cover the floors overnight, go to deliveries overnight, do a lot of work in the ED overnight (although to be fair, there's a trend recently towards more and more fellow/attending support in all hospitals). This also means, unless they've been having attendings or NPs on the floor overnight, that the acuity of what they'll admit to the floor there may be much lower than what typically gets admitted to an academic peds hospital.
Just stuff to keep in mind. If you're looking to shape a new program and don't mind some hiccups in the first year or two and not being "essential" to the hospital doesn't bother you, it could be good for you. You can take a look at Hopkins All Children's program in Tampa, they just started that up in 2014 and it seems like it's still going along alright.