Yes, a 2.6 Tomahawk would be perfect as rear tire on the hardtail!
The terrain here doesn't wear down the tires all that much, but the edges get rounded off and degraded and side knobs get destroyed from loads of off-camber. So my center knobs were quite ok while the side knobs were looking terrible. Cut the center ones down to about 1.5 mm.
Do give it a try! It's sortof a win-win either way :)