The elders + Hiruzen and Danzo were alive during the era of the first and second Hokages but as children. So they're all somewhere around 90 years old.
Team Tobirama consisted of Hiruzen, Koharu (elder lady), Homura (elder guy) and of course the 2nd Hokage.
They were alive when Tobirama was Hokage so my guess his the same age as Hiruzen.
Hiruzen was about 68 - 69 when he died and that was about the time when Naruto was 10, so he dies when Naruto was 16.
I'm going to say he died at the age of 74 - 75.
They are all around the age of Hiruzen, who would be 72 in part 2. They may all look like they are in their mid 80's, but they are all early to mid 70's.