Well considering you've already got 2 dark types, I'd rule out Incineroar and Greninja you go with a Protean set without (emphasizing) dark moves.
With Absol and Nidoqueen I know you've got some Earth, Poison, and potentially Fighting and Fairy moves down (particularly with Nidoqueen's awesome movepool)
I'm also not sure if you're planning to use Umbreon as a tanky staller (Toxic/Protect/Wish) or as a tanky fighter (slap on a Psychic and/or Shadow Ball)
So currently you've got a staller, a jack of all trades, and a straight up physical attacker.
With that said I like to plan my teams around type coverage, so maybe Delphox (unless you've got sufficient psychic and ghost coverage)/Charizard (Mega Evo + Dragon Claw), Empoleon/Primarina/Blastoise (only for the consideration of his mega set), and Decidueye/Sceptile.
I'm sure other people will have differing opinions