I have no hands on parenting experience as yet, so feel free to disregard what I say. I am, however, a master at compromise and conflict resolution

DF seems defensive about his 'routine'. This can be hard to work around. Maybe the easiest solution is for you both to sit down and come up with a plan you're BOTH ok with. Consistency is what's most important, and it seems if you both do things so differently it's going to result in more conflict between the two of you, as well as unsettled little ones. It may mean you have to start from scratch again, but if you can find a middle ground and he feels he's had input in how things are done, it's worth a go.

I hope I've been somewhat helpful, but if not, here's a simple

Change is always hard, I hope you can work out a system which works for you both.