Shuma Gorath's only connection to the Guardians is that it is connected to the Cancerverse (where Nova and Star-Lord got stuck with Thanos after the Thanos Imperative) but even that is a bit of a stretch.
Shuma Gorath is a Doctor Strange villain why would they use it for Guardians whn they plan on making Doctor Strange movies.
and the Black Panther one is obvously
If they ever did a movie for him why would they use 2 of his 3 known villains in one movie