I think they were all decent musicians, though not on par with the Wrecking Crew session musicians who played on their records. Supposedly, Mickey was the best guitarist when they formed the group.
Mickey was primarily an actor but with a good voice. He was a child actor in a successful TV series. Davey was experienced in musical stage theater having co-starred in a successful theater production of “Oliver” in London. Mike and Peter were musicians and Mike was the best. Mike actually had a hit song post Monkees with the beautiful song Joanne.