I'm no expert, but I can at least take a crack at them. Here goes nothing:
*Floppy drive: Definitely could be bad filter capacitors, but hard to say for sure. Rather worrying that the line fuse didn't pop first. If it was the filter caps, check for collateral damage in the area. Rectifier bridge(s) and voltage regulator(s) are likely candidates; hopefully, none of the more major components (like the power transformer) let out its magic smoke...
*C=64#2: Sounds like a graphics issue, perhaps the VIC chip or one of the other graphics ICs. Check
this list against your symptoms.
*C=64#3: Again, sounds like a bad chip or two. Check the above-linked list against symptoms.
Fortunately, spare parts are fairly plentiful (apart from certain chips, like the 6581 SID, and even they can still be found). Check the following site for more repair info:
http://personalpages.tds.net/~rcarlsen/
Good luck!
-Adam