I guess it depends on how many flights are in/out of each airport and how comfortable they are waiting for plan b if they can't get on first flight.

My husband's father was a total pain in the hiney about pass travel. He had a buddy pass for his "lay by side" so it could be an issue at times for seats. He always wanted to go someplace like Vegas (which was one problem) or Portland Maine (on an RJ, minimal flts/day) He'd start with calling 3 months in advance to have them listed and then ask about seats every 2 wks. Oh yeah, and he didn't want to fly from DTW (first home) or ORD (later home) so he'd drive 5 hours to leave his car here for 4 days. Talk about frustration!! So, if the folks are NOT like that, they might be able to successfully nonrev w/out driving you crazy. Fares might be so low right now, they could do well with tkts. Sorry I can't help w/your pass bureau issues but I thought I'd share and hope your family is much easier to deal with!!