UNH is the only team that plays Maine home and home same weekend, mostly because they usually end up playing a neutral site game somewhere in Portland or Manchester, and it's more drivable. But since they're playing four this year (two are considered OOC) I don't know which are considered home/away in conference. But that would account for UNH's even schedule. The thing is, there's no good way to do it. But they will not sacrifice home-and-homes each season when it's possible to do it, to answer your question about two at same site alternating years with non-UVM/Maine/ND schools.
In all of the years prior to ND joining, HE didn't have an even home/away game total either. There were 10 teams, you played three against everyone (2 home, one away or vice versa) for 27 total games, so you'd have five 2H1A series and four 1H2A each year (14H13A), and then switch the next to 13H14A.