Elaugaufein
Member
The only time I've seen Gravity work really well in doubles was in VGC16 when the format allowed Primal Groudon. Boosted accuracy Precipice Blades that could hit levitaters was really strong. People really liked Gravity/Hypnosis Bronzong. I know some Pokemon like Xurkitree and Exeggcutor get Hypnosis so that might be worth looking into.
Just looking at the list of Pokemon you've put together nothing really strikes me as strong enough to justify the set up time needed for Gravity. Thunder and Blizzard are great but weather is so much easier to set up. If you really want Gravity to pay off you might have to go for something really gimmicky like Sheer Cold Lapras or Fissure Gastrodon.
Is Fissure effected by Gravity ? (Other than being able to hit Flying / Levitate), it ignores most other accuracy/evasion modifiers other than the Guaranteed Hits.