A few general points:
(1) while there are positions in JB’s O, not everyone at that position does the same thing. Stu Douglass, THJr, Stauskas, and MAAR had pretty different roles based on their abilities and roster make-up. Same with GRIII and Duncan Robinson.
(2) you are what can defend – not entirely true, of course, but sort of.
(3) the roster/depth chart matters.
What this means for Poole, Iggy, etc. Poole, at least to some extent, is a victim of the roster. We have Simpson, Simmons, and MAAR at the 1 and 2, and Brooks has looked really good and has to play somewhere – but two of those three are leaving next year. Conversely, Livers benefits from the roster, as at the 4 we have . . . guys whose best position probably is the 3, especially defensively. If DJ Wilson stays and MAAR gets injured preseason, the minutes distribution be completely reversed. There’s a long way to go this year before we look to Poole’s chances next year, but there’s little doubt that there will be a lot of opportunity for Poole next year at the guard spot.
Iggy can create from whatever position he plays in and the offense can concentrate from various positions. For instance, as kturnup alluded to, in '13-'14, Nik, Caris, and GRIII (and Irvin) had significantly higher usage rates that Walton, even though Derrick was “the PG.” Iggy might share the court with, say, Livers and Matthews, but based on (a) defense and (b) experience in the system, it is unlikely he will be the 2, especially his freshman year.