1. and honestly the most important thing what CG said for tiers is a snapshot but not an exact layout. don't just reference it for any "this unit is beating that person"
To be clear, this certainly does not hold universally true for all units but is a rough rubric we can use to discuss this topic in more detail. There are many exceptions to the rules (in the name of fun and interesting gameplay) that exist but overall this is a good snapshot of how we approach power.
2.
IF and only if you use their teirs then Gsky and JKL ar in the same their so it's valid that one can beat the other.
3. Gsky is an Epic confrontation character, the second-highest rating for an unlock, below that are hero/villain journeys. Thus in my opinion it's logical that a Gsky team could beat a JKL team better.
3.5 plus you said it was a damaged Gsky meaning preloaded TM, without seeing what it was it's even more likely that he could beat JKL from that TM advantage alone
