Here you go - as far as know anyway!
1. I have Look Keo Classic (i think) pedals on my new bike and cleats to match, i have older sets of Look pedals - will the new cleats work with them? NO
2. I have a pair of Shimano pedals - no idea of model number but they are road, what cleats are required for them? NEED PHOTO TO SEE WHICH MODEL THEY ARE
3. I also have a set of Miche pedals - to attach to a Miche crankset - do i require Miche cleats for these? AGAIN NEED PHOTO TO CHECK ON THE DESIGN. THEY MAY BE A LOOK CLONE
4. Are cleats interchangeable between pedals? NOT NECESSARILY. SOME DO, SOME DON'T! (SORRY!)
5. Is it possible that some cleats may work with some pedals and this can be found by trail and error? BE IT ON YOUR OWN HEAD - LITERALLY - IF THEY DON'T AND JAM UP ON YOU. SOME WELLGO PEDALS WORK WITH SPD CLEATS FOR EXAMPLE, OTHERS (EARLIER ONES MAINLY) DON'T.
I'm sure someone will be along soon to put me right if I'm not correct. I often am you know
Today is the yesterday of tomorrow.