I don't believe either Dior or McNeilly should be expected to be immediately handed starters minutes or to initially be significant contributors. IMHO, they were recruited primarily to plug in the following season when Burton, Sibande, Elliot and Cummings have all completed their eligibility.
I see both of these guys just getting back-up minutes and "garbage time" minutes---unless there are injuries to the 4 more experienced guys who will be completing their eligibility. Caveat: might be a somewhat different scenario if either Dior or McNielly demonstrate that they are ready for ACC level play AND willing and able to be unselfish "team" players.