What operating system are you using on the system in question (#1)? The following link describes how to do what you are asking about with Windows and Linux:http://en.kioskea.net/faq/616-multicore-cpu-how-to-disable-a-core#procedure-when-using-windows-vista-7-and-xp
For question #2, the answer is probably "Yes". However, this info is on the Intel website that warns....
Warning: Processors not specifically listed by type and rated speed may have requirements that are not supported by the workstation board's design. Use of unsupported processors may result in improper operation, damage to the workstation board or processor, or reduced product life.
Looks like the CPU family is supported so I can't imagine it would be a problem. If you can find someone with your config to verify, that would help. But it does appear that the config you are asking about will work.