I dont think its impossible for full time jobs at all. It's really easy to hammer isolation workouts for 30 minutes and get good volume in, you dont need 90 minutes of isolation exercises. Just rest shorter periods anyway. as long as you can get 20-30 minutes after work you can hit whatever weak muscle groups you want. Days that aren't as busy, take 45 minutes and rest longer between sets in your second workout. Kids would complicate things more than a full time job imo.
I do like the low rep first/high rep later set-up very very much.