Help with 17 yo Advent Heritage 8" woofers

Hello,
My father has a perfect pair of basically unused Advent Heritage tower speakers. Problem is the surrounds are rotted. Two of the drivers were destroyed in an attempt to refoam them. So refoamimg is out of the question at this point.

I was wondering if anybody has found an inexpensive suitable replacement for these or knows anything about the TSP of these.

I was thinking of repairing the two remaining drivers, measuring the TSP, then trying to find a suitable replacement. Figured I could sell the two repaired ones.

I think it is a 2.5 system, can anyone confirm this?

Also, does anybody know if they are 4 or 8 ohm drivers, dad doesn't have a DVM available or I would have him measure the DCR.

Any help here appreciated.
Thanks,
Jeff