Each PTP stands alone. The loss from one can only offset income ffom that one.

Unallowed losses do not go on 8582 for PTPs.

What do you mean by adding "material"? Unless your client manages the PTP I don't see how they can materially participate in the activity of the PTP.

Prior year unallowed losses get entered in each K-1's screen, down toward the bottom if it works like Lacerte.