Yes, the duckings will be completely fine when left with the mother.
Technically, it is possible for some casualties, but a few kiddie pools shouldn't be a real problem
I have some plastic kiddie pools for my muscovies. I haven't let my ducks brood in a long time, but you can dig a hole for the pool to go in. Deep enough to where the ducklings can step right in. Multiple pools are always better.
You could make your own pond if you have the resources and space. Something like this.
https://www.tyrantfarms.com/how-to-build-a-backyard-pond-with-diy-biofilter/#pond_expectations
I have no clue how well this project works since I've never done it.
Muscovy broody should work out just fine!