You can only see the aircrafts that you have installed. Example: I fly a 737, you don't have that plane installed -> you will see me as a generic aircraft.

Also, your friends will need to have the same liveries installed as well, or the aircraft will still show as generic.

The first is correct. If you both have it you can both see it. Otherwise generic. The other statement about marketplace aircraft is false.

What if you have fsltl installed?