This is my understanding on tipping.
I believe that Mousekeeping is considered a non-tipped position at Disney, however the CMs who make up your room are permitted to accept tips. The amount is discretionary- I have seen suggestions of $2 per person per day, I typically leave $5 per day whether it is just my husband and me or if it is the whole family.
Additionally, at club level, there is someone who turns down the room (and leaves chocolate)- I typically leave $2 for turndown.
As far as tipping the Club Level CMs- I have been told that CMs are not permitted to accept cash tips, but can receive other gifts valued at less than $75. I have heard conflicting information about whether gift cards are considered to be "cash". In the past when I have stayed club level, I have brought some local treats- a New England cookbook, small bottles of maple syrup, candy or Starbucks or Dunkin' gift cards of $5 or $10 for the CL staff to share.