See Intel® Xeon® Processors 5400 and 5200 support, as those CPUs has different power requirements, althought the socket is the same.
If you can boot the system already, yes you can update the BIOS with all those components installed.
As for the fan heatsink, both links you provided are same model (D39267-002), and it's goof for Xeon 5xxx series up to 120W.