A suntour shifter would work fine with shimano rear block as long as you are prepared to run the shifter in the friction mode, (Non Indexed) if you run the suntour shifter on a non suntour block the indexing will be out by a bit
Interesting to hear that 8 speed combo will work - how so?
Also to chuck another related (hoping non-thread hijack ) question into this - how would a SRAM road cassette work on a current 8 speed Suntour MicroDrive system? Would the cassette even fit onto the hub?