Tell her she will need to book a baby cot for on the plane. But I don't think she can book a ticket until the baby is born and has a name! May want to check that point out now if she is booking tickets.
Sunshine is much stronger in Florida so she should make sure she has hats, baby sunglasses etc.
Take her own car seat for use in the car as US car hire companies charge a fortune and the seats they provide are often crap!
Take a buggy rather than a pram so she can use it in the airport until she gets on the plane.
Sam100 is right in that the airlines probably won't let her book the bassinet until the baby is born. We tried this at the end of last year booking flights for this easter when our baby would have been 4 months old and they wouldn't let us book his ticket or reserve the bassinet. We therefore had to book our seats to reserve them and then phone up when he was born and add him to the booking, extra charge of course!
Many villas in Florida are fully equipped for little ones so she should double check with the company who they have booked with. I have a villa in Orlando and have a high chair, pack and play (travel cot) - used to have a proper cot but apparently the law changed a few years ago out there and the management company said we had to replace the normal cot with the travel one. Also we have a car seat there and a small lightweight buggy for guests to use although most take their own buggys (or buy a cheap one on arrival)
A decent villa will also have a blender etc and the baby good in Florida is pretty good although she may want to take her own specific brand of formula milk.
Also agree ref the car seat hire. We hired a seat 2 years ago and it would have been cheaper to buy one! We therefore bought a 'sit 'n stroll' which is a fabulous car seat with a handle that pulls up from the top and wheels that pop out the bottom which is fabulous for travelling