The LT-40 is a very complete kt: hardware, wheels, engine mount, spinner all included. That makes it a real bargain for the price, and as many others have said, it's a great flying plane to learn on. The instruction manual is detailed and good for a beginning builder, I think. From your small electric to a 4-star would be a pretty big jump. I have no first-hand knowledge of the Balsa USA plane mentioned, but their kits are great.

Do you have a good local hobby shop nearby? If not, that's probably a good reason to go with something pretty complete like the LT-40.

I'd strongly advise against retracts. You'll have enough hurdles with your first build. Retracts are very cool, but they can also be a major pain. And the landing gear on the plane you'll be learning to fly on will get beaten up pretty badly. Trust me: your first landings with a glow powered plane will not be pretty. Better to beat up some bent wire than an expensive and fragile set of retracts.