Alcohol ink — Works. Note, however, the alcohol does break down the epoxy somewhat, and can cause some weird / interesting effects. So don't over-use the ink, and know what you're getting into. You shouldn't have a problem using enough to get the color that you want though.
Acrylic paint contains water, and when you try to thoroughly mix the paint into the CA glue, it acts just like putting accelerator on CA glue (which is what it is) — the CA glue cures within seconds.
Alcohol inks — Usually doesn't work.
Usually inks don't use pure alcohol, instead they might use 91% isopropyl alcohol, for example. This means that a little water is present in the alcohol inks. And water means instant curing.
Mica powder, pigment powder, or glitter — These work great.