These are standard PC parts. I ordered them brand new from Amazon. Sorry no links as I'm on mobile.
StarTech.com 230 Watt PS2 Replacement Computer PC Power Supply - PS2POWER230
StarTech.com 50x10mm Replacement Ball Bearing Computer Case Fan TX3/LP4 Connector FAN5X1TX3 (Black)
I used a 128GB ram stick I had from a 2001 desktop mac.
In looking at your picture, I don't see the metal clip on top of the battery holding it in (and I think making the ground connection, although that could be happening from the side) Don't know if that affects booting.
Edit: there are apparently 3 different motherboards used in pin2k so there could be different battery holders.