There is room for both on the roster next season. We do not have a PG signed in next years class, so it depends on where Teagues head is at. He strikes me as a "me first" kinda kid, which I don't hold against him. If that's the case, he should probably try to go and then play his way into guaranteed money from the 2nd round.
However, I will be clear that while Harrow can shoot the rock better and is a solid PG, Teague still has a higher ceiling with more upside. More quickness, better defensive player. His stats over the last 10-12 games of the season have been outstanding. His sometimes stupid shot selection comes in horrible spots in games, which leads to a 5 or 6 point swing, which often overshadows what he is doing really well in a game.