I think, from a statistical standpoint, as some have touched on, you don't need a great distributor to be your 3rd string PG. Not saying it's not great to have that, but it's not a necessity.
All you need in that role is someone that can effectively initiate offense. Someone that can get the ball up the floor and initiate an offense that gets a good shot most possessions.
Statistically, then, I think the most important metric is finding a guard who handles the ball quite a bit and has a low turnover/100 possessions number. If there was a stat that measured turnovers/100 possessions or shots/100 possessions with that player on the board, that also would be good.
This is why I think Rupert and Sidy might be adequate if Banton is gone. All they have to do is get the ball up the court and get us into the offense. Even if one of Scoot or Jrue (presuming Jrue's even here) are out for a game, Deni's going to be running a lot of PG, too. A poor-man's John Stockton isn't required for this roster spot. You don't even need to roster a spot specifically for it. All you need are a couple of other players that can get us into the offense. Therefore, being a better player should outweigh rostering for positional need.