Disclaimer: we have not had children yet, so I cannot speak specifically to losing pregnancy weight, but my wife is a longtime runner/yogi who used to consider a Jillian Michaels DVD (relatively similar to the workouts in 21-day fix; her sister has done the 21-day fix program a few times).
She started doing some serious kettlebell workouts with me about two years ago, and this year has added legitimate barbell training. Nothing too crazy, she basically just comes to the gym with me and does squats and deadlifts once a week, but even that has made a dramatic difference in her strength and (more pertinent to your question) her physique. I think that one of Christian Thibadeau's programs would be a terrific idea but just to be clear: do you mean Chad Waterbury's Sexy Female Training, linked below, or something else?
Honestly, you don't have to do "serious weight training" like the big bodybuilder-bros for it to be worth doing some lifting. Getting a few sets of some big compound movements a few days per week can do wonders, and as you noted, several of the authors here have written programs specifically for people like yourself.