could you assemble this ahead and cook later?
I don't see why not. When I make lasagna, I commonly make 2 and freeze one for later before it is cooked. I generally use the no boil noodles & no sweet potatoes, but otherwise the process is the same. If you're just going to refrigerate it, make sure to pull it out of the fridge at least half an hour before baking. You will likely need to bake the lasagna a bit longer - 10 minutish is my guess.
Oh most definitely!
You could hold it refrigerated but I'm skeptical about freezing it even though Marie Callendar does. If you'ever get to taste lasagne in Emilia-Romagna it will change your opinion on the whole process which involves house made sheets of pasta---not difficult if you have equipment. And then you make a ragu, and a balsamela as a binder and blah, blah....Lasagna by the way is a singular term meaning one "leaf" of pasta. What you really need are lasagne (plural). I hate to be pedantic but there you go.
Lasagna seems to me to freeze well after baking, when I was single I had to freeze my leftovers or throw them away. I don't think it would keep in the frig well before baking for more than a few hours. It's not quite the same reheated but it's ok.