Hey, congratulations! You've got the best OS9 machine there is, as well as a solid MorphOS box. You might want to re-do the thermal paste on the CPU heatsink, though, as a preventative measure - my MDD came with it cracked, dry, and utterly ineffective, and suffered from constant overheating, but I slopped some Arctic Silver on there and it runs great now.
As for the mouse and keyboard, I can't speak for wireless, but I've yet to run into a wired USB mouse or keyboard that doesn't work with USB Macs.