Events+ -I'm attending button + marketpress

Good day,

I have 3 questions:
1. When a client clicks on the I'm attending button it doesn't disappear or update, in other words they can click on the same button 10 times to say they are attending. Is there a way to fix this so that once they click that they are attending, then it wont let them click the same attending button again.
2. Is there a way to completely remove the RSVP buttons when the events+ plugin is integrated with marketpress, so that the market press purchase function works as the RSVP function?
3. Where can I find the files to edit the appearance of the marketpress pages, I just want to pretty them up a bit with different background colours etc.

Thanks for your help.

Cheers
Ela