The PCIe number is the number of lanes the slot uses. "Normal" 1X slots have one lane. 16x graphics slots have 16 of the 1X lanes put together to form one "new" slot with 16 lanes. Same thing goes with 8X slots on SLI boards and the occasional 4X slots that are on some boards. They're not diffrent versions or anything.
SATA II is pretty much just SATA 150 bumped from 150MBs to 300MBs and with Native Comand Queing(NCQ) added. It should probably be called SATA 300. SATA 150 drives work on SATA II controllers and while I would hope that SATA II drives work on SATA 150 controllers, I never looked into it.