Let's just say for argument's sake that both Howard / Battle return [no real reason to think otherwise]. These two will occupy two of the three perimeter positions. But that means that there's a hole at whichever position these two don' fill.
Said hole would need to be filled by an incoming recruit--either a PG, SG, or SF who is starting caliber--because we don't have anyone on the roster returning [with apologies to Matthew Moyer, who is more of a semi-versatile 4 than a 3] who has the game / skills to fill that third perimeter role.
Had we landed Green, he would have started at 1. Frank would have slid over to be a combo who chips in a lot with ball handling / distribution responsibilities, and Battle slides to 3 -- where his size is more than adequate to play the back end of the zone.
Since we didn't, right now Howard projects as the 1. Battle could play either 2 or 3 [depending on personnel and what's best for the team], but we still have that third perimeter spot as a gaping hole.
A wing like Tucker might be able to fill that hole. He'd play 3, which enables Battle to play 2.
Bottom line: we need to add one starting caliber perimeter player -- be it a 1, 2, or 3. Once that's accomplished, we need to add rotational depth behind that group, as right now there is none to speak of. I agree with your post above that we might be able to get by at lead guard with Howard and Battle backing him up for brief periods. But we can't just roll into next season with no backcourt / wing depth. This is what's most frightening to me about next year's squad.
Lots of work still to be done on the class of 2017.