Lately there have been a lot of threads from people saying "I've tried everything, and nothing works." Or "I'm training like crazy and have my nutrition dialed in but I'm still fat." Your thread is WAY better.
You already have a history of success with working out regularly and being in shape before the baby. BUENO!!
With a toddler and nursing school - BUSY!! - I'd fit in a short workout at the university gym before class a couple of times per week if you can, but otherwise I'd walk and run around at the park with your daughter, do step-ups to the park bench, chins on the bars, pushup variations.... WALK with stroller, and train at home with the hubs so you can tag team the baby between sets. Since you are familiar with Crossfit, you could do something similar at home with him, or maybe do a short full body routine at home? Twice a week lifting at home, if you're finding the time to get to the school gym a couple of times, would be fabulous.
That said, the part that NONE of us really enjoy is modifying diet, but that's where it's at, unfortunately. No matter what you do at the gym, you will "eat your results" really easily. You will have to find a calming and enjoyable, and celebratory substitute for food. ERG. I can totally relate. My downfall is chocolate, and lots and lots of chips and salsa.
Honestly, I had my three kids before I started lifting and I lost my baby weight mostly by being mindful about eating. I did a lot of walking, and had a morning jogging routine. Wish I'd known about lifting then. My BFF just lost all her baby weight coming back from her third pregnancy by taking Zumba classes and using weight machines at the gym after class, but the MAIN thing was she stopped the high calorie mocha drinks in the morning, and stopped eating cookies and ice cream in the evening. She loves taking Zumba classes, so that's her thing and she's doing really well with it in terms of fat loss goals.
About diet - There's a lot of information on this site. Personally, I like The Zone, and a lot of people who lift can do pretty well with Zone macros (30% Pro, 40% Carb, 30% fats). I like to eat small meals 4-5 times per day, but other people do really well with other diet plans. The trick is finding what is sustainable for YOU.
If you follow Jamie Eason on FB, she has some nice daily workouts, complete with videos. Some machines, and some with free weights you might have at home. I have a friend at the gym who just follows her programs and loves it. She also has an eating plan, and recommended food list. I just finished reading the Christmas Abbott book, The Badass Body Diet. You might like her since she's a Crossfit person and so that would be familiar, but her book has a healthy foods list, eating plan (which I haven't done), as well as a lot of BW exercises in the back that you could use at home. Nice stuff for conditioning, and the whole book is written for women specifically. I checked it out from the library.