All those engines will work, I had 14 different engines on mine from a Testers .35 to a OS .60FX two strokes, VT.49, Saito .50, RCV .58 four stroke engines. The two engines I liked best where the LA .40 and the Saito .50, the plane flies on it's wing not the prop, the worst engine was the OS .60, it just overpowered the plane. With the LA .40 you should fly it at halve throttle most the time. You're just starting out so I doubt if you have, or want, a big collection of engines, so I'd say get a .46, it's more suitable for more types airplanes down the road, and will work fine in the LT-40.

The radio will work fine for your needs. The more expensive radios don't help YOU control the plane any better, they would make it easier to set up your plane. The radios that have different model memories would allow you to buy just a flight pack, but if I only had one TX I would want to have another so that if one has a problem, like you forgot it on and the batteries are dead or 3 guys at the field are all on the same freq, you could fly with the other TX.

Do hook up with an instructor, he will save you much grief and time.

The flight sims are also a good investment if you're new, they get you past the aileron reversal problem quickly. I just bought one for myself, at $200 it's much cheaper to learn to hover that replacing my 100cc Yak 54 every time I goof.