Crystal  CPLD interface
You shouldn't need a load capacitor, but if you're nervous then leave some PCB lands to mount one just in case.
Again, probably not necessary, but I can't think of a reason not to do so.  Maybe test it both ways, it's just a fuse setting and you can change it later.
You MUST connect EVERY SINGLE power and ground pin to the appropriate voltage.  No exceptions.  You don't need a separate supply, just connect all the 3.3V pins to your 3.3V rail, all the 1.8V pins to your 1.8V rail, etc.  Also, you should mount decoupling capacitors in close physical proximity to every power pin; Xilinx will have documentation on the recommended power supply decoupling for your specific part and package.
The CPLD and crystal can share the one supply.