Your engine has indeed been out of production for a while now, but there's nothing wrong with it. Diesel isn't necessary, but if you have an old jug of glow fuel submerge the engine in it for a day and start working everything loose.Take the carburetor and backplate off to do this.
Futaba still makes good radios, better than spektrum, IMO. All 2.4ghz radios use a frequency hopping system with a transmitter identifier number. There is no more reserving channels or interfering with other people's planes.
Servos are universal, but receivers are not.
SAFE can be helpful if you are learning on your own, but I think anything but using it for added stability is a hindrance to learning to fly with an instructor. There will never be a better system than the one devised in the 80's- an experienced pilot buddy boxing with a student and explaining how and why to fly correctly.