looks like a plan to me...

just make sure you master that spacewalker before you step up to the 'stang'.

as for the radio gear. I would keep the stuff in the planes as they are but slowly upgrade to something that is available to you as you get new stuff. (ie is your local shop carries futaba and your flying buddies use futaba I would suggest looking into futaba later on)

but for now the airtronics should be fine. also you might find you like them better than the other brands, but thats up to you.

as for the servos you shouldn't need to change them out. the only concern is that you might need to rewire the connectors or get adapters for them as I think airtronics uses a diffrent wireing configuration then the rest.

good luck.