Good job @KathiQuacks -- I am sure that they will look good with fine feathers in a couple of weeks getting outside and having room to preen and dry off.
@VicktoriaGiuergia Small ducklings always need supervised swimming in shallow pans as they are not waterproof. By 8 weeks old, ducklings can have access to a kiddie pool with stones/pavers/wooden ramp so that they can get out. This is not wrong @VicktoriaGiuergia. Yours that drowned must not...
The living circumstances sound a little cramped for 4 ducks. Can you fix up a temporary pen for them to be in outside during the day, even if they have to come back into the shower at night?
I think your ducklings may not have wet feather they just don't have a lot of room to preen after...