Kuma might be worth it because of his damage potential and decent mobility with his backdash and Hunting Bear stance. Although i would consider him more a heavy hitter than a grappler. Just look at the Kuma forums, people love him!
I would say that Marduk is scary. His grab is the fastest in the game, especially EX is great. He has solid dashes, long range normals, his aa-grab and also some combos of his own. His lk is very good.
Both probably won’t win Evo, but in my opinion, they are solid.
Gief I think is one of the best defensive characters in the game. He can deal with pressure because of his lariat, grabs, and st.,cr.lp and st.lk. His lp.spd has great range, lariat deals with jump ins and cr.lp is very good.
But he really has problems getting in against pokers like Vega and especially against heavy zoners. Almost impossible with the roll nerf and especially the walkspeed and st.mp nerfs.
He also doesn’t really have good combos.
Hugo is just crap.
High damage, but how do yu get in to land it except after tag? Also without ex he is free under pressure.
I don’t know anythiing about Abel.