The plane looks like a Great Planes PT-40 As the name says it's a great plane to learn with. I looks like you are missing the fuel tank and the cover for it - the cover is simply a piece of balsa that is covered with Monokote. I used Marvel Mystery oil for all my engines until I found K-Mart air tool oil. It's the same thing only much cheaper. And I have recovered several engines that were stuck with disuse and gunk and never had to take them apart or even off the airplane. Put the Marvel in the carburetor and let it soak a while then turn the airplane over and let is soak some more. Then you should be able to slowly turn the engine over with the prop. It will loosen up.
The transmitter and receiver for 72 MHz have to be the same channel number. Futaba and Hitec 72 MHz FM transmitters and receivers (7 or less channels) are pretty much interchangeable. Tower also made a compatible one.