My pick for T'Chaka:

Real talk? There are only 2 real contenders for T'Chaka, although I'm sure both of them will not be given the nod.
Those real contenders are:
MICHAEL JAI WHITE

and WESLEY SNIPES

But they won't get the nod.
Especially since Michael Jai White was almost God-created to play Luke Cage...whose name I'm surprised I haven't heard more of than I've heard of TChalla visavis movies are concerned.

And Wesley still is...

So Hollywood will prolly get someone like TAYE DIGGS, who people forget carried action in EQUILIBRIUM quite well...

and the much overlooked MORRIS CHESTNUT, who is a major heart throb to our WOC...

Morris would probably be the front runner for LUKE CAGE [ even though he really shouldn't be; he should be a definite second to Michael Jai ] if Marvel brought him out soon, but they're not gonna do that so by the time they make that decision? Morris will be too old for the role.
You know who else would be a dark horse longshot but whose proven he can handle physical martial arts choreography well?
Yall remember this here movie?
And...for real...honorary mention for THIS guy, because of his role playing THIS guy: