If Bannon is not welcome then Trump should insist that Sen. Tim Scott be present at the meeting. That provides Trump with an ally at the meeting and prevents the CBC from making spurious charges like pretending Trump uttered the n-word in their presence, etc. Having Dr. Carson attend would also be a positive move.
If the CBC really wants to discuss issues and not just grandstand, they should welcome people of color that Trump happens to invite, yes?
BTW, I have not hear yet whether the CBC allowed Rep. Mia Love (R-UT) into the CBC but they famously rejected Allen West when he tried to join. Rep. Love should also attend the meeting and be a prerequisite for meeting at all.