1. Can 3 1/5 and 5 1/4 inch floppy drives be combned?
Yes. The 3,5" drive comes first, the 5,25" drive goes to the 3,5" drive. I'm not completely sure but I think you can connect upo to four drives but only two of each kind.
FAQ here: http://home.swbell.net/rubywand/A2FAQs5MAINHALL.html#013