I'd say that's a good idea, a lot of the time people get defensive when you explain that they're hurting their animals, so it works better to approach it from a "helpful" angle, like, "If you separated them you wouldn't have to deal with another pregnancy!" or "They're so much fun to watch run around in a bigger cage!"
If there is a litter of 1 male and/or 1 female, you could also try asking if you could adopt one of the parents, rather than getting one from a shelter (like if there's a female pup, you could ask to adopt the mom and the female, or a male pup and the dad). That could be a way to convince your friend to separate her pigs, but depending on how attached she is to them specifically it might not work.
The fact that they're alone so much of the time could also be a reason you give to keep them at your house awhile, the mother at least. You don't want a delivery happening at the school.
Sorry I don't have much to say about the cage construction, my cage is a pretty basic C&C cage, just now saw your earlier post and thought I'd give my two cents.
