I've not maintained the whole of my loss for too long, but I've "maintained" the first 10% for about a year now, at a guess so I suppose I can scrape in! Anyway, I'm intending to maintain for longer than that doing what I'm currently doing, so I'll answer the questions anyway.
[*]Engaging in physical activity, ~1hr/day equivalent to brisk walking
Yes I'm training for a marathon so I'm running 20 - 30 miles per week most weeks (which will be increasing) as well as a cross training day and plenty of incidental brisk walking which I don't count but probably adds up to another half hour or so most days.
[*]Eating a low-calorie and low-fat diet
I don't track either, but I think it's fairly low calorie and low fat. When I'm choosing foods I do look at their calorie and fat content to make sure they're in the right ballpark, but I never add up daily or weekly totals.
[*]Eating breakfast
Yes. I don't eat it as soon as I get up (I usually exercise first), but I've almost always eaten something fairly substantial by 9am.
[*]Weighing in on a regular (usually daily or weekly) basis
Yes. Every time I go to the gym (where the scales are) I weigh myself. I don't do that every day because sometimes I run outside or have a rest day, but if I'm near the scales I always get on them, to check I'm within my current 2 or 3lb range.
[*]Eating the same on weekends, weekdays, holidays, etc-consistency
Pretty much. I'm sometimes a bit more creative at weekends because I have more time to cook, but it's basically chosen on the same basis and planned in the same way as during the week. I'm sometimes a little more relaxed, but I do my long run on Sunday which means I need more calories anyway, so any increased eating isn't a binge, it's just balancing out my needs when I'm most likely to want to eat it
[*]Preventing small gains from turning into larger lapses
I don't know yet based on my proper goal weight, but certainly while losing and "maintaining" that first 10%, I've never let small gains get me down and I've got straight back on track. And I know from all my time on here that nipping gains in the bud is definitely the way to go, so that's what I'm
intending to do!