Sources describe almost every surviving Iroquoian language as severely or critically endangered, some down to a handful of elderly speakers, and give figures for individual languages (Mohawk, Cherokee) without ever totalling the family, likely because the count changes quickly and no body tracks it in aggregate.
What would resolve this A coordinated census or revitalization-program report aggregating fluent-speaker counts across all living Iroquoian languages at a single point in time, which does not currently exist.
OpenNorth American indigenous linguistics and language revitalization studiesWikipedia: Iroquoian Languages