I don't think I had enough coffee this morning.
The original idea should work as long as the relay it's using is rated high enough. IMO a 30 amp relay would be minimum.
I think I understand your original question correctly anyway. All you are interested in doing is getting rid of the key and using a key fob type remote to turn the ignition on but still having to push the starter button on the handle bars to actually start the bike.
As far as a complete remote starter system goes, it doesn't make much sense to me for a motorcycle, especially a carbed bike. The remote would not work the choke so the engine would already have to be warmed up enough to start without it.