TheVaultDweller
Front line cannon fodder
Initial round: I would give it to T'Challa, because of the suit's damage soak. He took a full-on metal arm uppercut from Winter Soldier and it barely fazed him. Hell, other than being knocked around a bit, virtually nothing that hit him while in his suit really gave him issues. It'd be a drawn out fight though, as Diamondback has better striking feats than T'Challa does, and even an extended beating couldn't put Luke down.
Bonus Round 1: T'Challa with more ease, as Luke has limited feats on Jessica Jones, and, other than tanking the bar explosion, they are below the stuff from Luke Cage.
Bonus Round 2: With just Jessica Jones, I would be inclined to give it to T'Challa. Cage still has him in overall durability IMO, but he was nowhere near as impressive as he was on his own show.
Bonus Round 3: Again T'Challa. Like I said, Luke was pretty weak on Jessica Jones. He had a notable power creep in between shows.
Bonus Round 4: Now here Luke has a shot. The robot arms are powerful, but Luke already showed he can take a serious beating from an opponent with comparable strength and keep going, even when holding back and the opponent gaining strength from Luke's hits. Panther has speed and skill, but Luke has more overall power in his body, and greater durability. Would be a tossup.