Yes you sure can color with oxides and micas.
I find that if you mix them in a small amount of glycerin before adding them they will incorporate better.
I'm not sure about Michaels colors I've never used them.
The liquid colors will most likely bleed in m&p soaps. In my experience, micas and oxides won't bleed, but the Michael's by me doesn't carry any - I have to order them online.
I haven't tried this yet but a friend told me recently that she tried to use the craft store dyes recently and it did not turn out good. The color ended up fading and bleeding a lot, according to her. I think she's using those powders you get from TkB trading now.
micas and oxides!!! i used the craft store liquid colors when i first started. they looked great for about a week. then my cute purple lilac soap turned gray. :0(
i used to mix the micas with water and heat in microwave until someone on this forum mentioned mixing with a small amount of alcohol before adding to hot soap. this works great. Thanks guys!!!!