We usually wire home and limit switches for axes direct to the inputs on the controller (0-7).
Is it possible to wire home and limit switches to CAN I/O inputs, and are there any differences in performance?
Yes you can wire Home and Limits to any input. ie the main processor box, the CAN I/O, EtherCAT IO etc. The ones on the processor are reacted to in 1 msec and those on the first 3 CAN I/O modules in 2 msec. Other inputs may take longer, though EtherCAT IO typically will be as fast as the EtherCAT bus cycle time. (1 msec or faster)