From a Bury point of view (even though I've been less involved this year so far), numbers are not currently a problem. After years of struggling to find 17 lads for each game (Ayres Rock you'll remember those days!), suddenly we've seen a huge influx of lads. The weekend we played Bolton and Rochdale A we had 25 missing (10 1st-team) and still field two full squads.
We've also got a good u-18s side ready to break into open-age next year and are trying to field a Masters team at Eccles this weekend, not sure how numbers are looking for that.
Most of the new faces are RU lads, with a few RL lads coming to us from other clubs. We're seeing many of them (especially the youngsters) preferring RL and committing themselves to us over their old RU clubs. That said, our good relations with local RU clubs has been key and we don't want to burn bridges! It also means that while numbers are great, they are often RL novices and can take a while to pick the game up.
No idea why Orrell chose to forgo promotion, seems pointless and not particularly positive for anyone. They may have had concerns over player numbers this year but that doesn't appear to be a problem. That said, other clubs have dropped down divisions over squad concerns so they wouldn't be the first. Other than Orrell and a couple of strugglers it seems to be a fairly even division so far with some good contests.
I would say clubs now need squads of between 30-40 lads to field a team throughout the summer. With holidays, weddings, festivals and weekend work you can have 30 available one week and down to a bare 13 the next. It's a problem with summer I don't think anyone foresaw.