Logic board compatability

I have an early 2011 MacBook Pro I5 2.3ghz, that has a bad logic board (out of warranty) and I might have to replace it. My questions are:

• Will any A1278 logic board work?
• Mine is an I5, can I upgrade to an I7 for the same model?
• Can I go with a newer board like a 2012 I5 or I7?

My underlying problem is that the laptop had water damage. I've removed the logic board and cleaned it using Isopropyl alcohol. I don't get any power or light on my power cable (I've checked that the power cable is good on another machine). I've tried replacing the mag power board but nothing.

Thanks,
Doug

MacBook Pro, I5 13 (8,1) OS X Mountain Lion (10.8.5)