Knicksman20
Superstar
This is what I think happened. I think he recorded a crazy direct diss to Pac before he died that was probably dope as fukk. When Pac died they probably thought about throwing the song away but it was so dope they decided to keep it on the album. But they changed it around to be more about anybody or any enemy and not specific to Pac and updated the song with other stuff, like the Cease crippled me line.
The problem is that they didn't change it enough and even though it was subliminal and not direct like the original diss, it still clearly seemed like it was directed to Pac.
I could be just giving Big and Pac too much credit but I don't think they'd be stupid enough to dance on Pacs grave, legally and morally. But I guess we'll never know...
I've echoed what you've said in the first paragraph as well. There's at least 1 more version of the song we haven't heard which was confirmed by Cease. The version with Cappadonna is on YouTube with Big talking over the beat