Nope, CT wasn't involved in PA, but a bunch of other Cavedog vets, including Jon Mavor, one of the main developers on TA, were.

I'm of the opinion that another CT RTS would be a project of 50/50 potential for TA fans. I love SupCom only a little less than I do TA, but I'm not a big fan of SupCom 2. On the other hand, some other old TA vets weren't big fans of SupCom, only to find themselves really liking SupCom 2. I never played PA, but I'm pretty confident I would be meh on it.