Quick update:
Removing Modular Powersuits seems to have fixed the issue. (Even know my world didn't even have any MPS things before) But any help that can be given would be appreciated, I will post over there too. Thanks.
I have removed NEI (also NEI Addons, NEI Plugins, and Walia) and I am still getting the same spawner crash. As posted above, I am able to go in and delete the spawner with MCEdit and all is well (with or without NEI installed.) However, if I go and find another spawner in the overworld or Nether I get the same crash.