I think the top 5 on his label line was more of a mind fuck and ego knock. Push is the president of GOOD Music, Drake said they stifle niggas over there, Push would be stupid to say he's top 5 on his label because then there's conflict of interest for the niggas he's supposed to be putting on and reaffirming what Drake wants niggas to believe.
As for stifling labelmates I think it was Joe Budden that said Drake has a whole label of niggas producing and writing for him in the OVO sweatshop. Outside of PartyNextDoor who has blew up on OVO records ?