I'm wondering if this works in FSX SE, and also contains the PMDG 777? Or do I need to get this seperately? Also how is it?

Both FS2Crew and MCE work in FSX-SE. FS2Crew is a separate purchase for the NGX and T7, MCE though is a one fit all type addon, but have unique profiles for many payware addons, including the NGX and T7. You can also create your own tailored   to your liking through a script. It also includes the ability to interface with ATC if you either use, default ATC, RC4 or PFE.