My 4 just peeped and chatted FOREVER! I held out hope for 10+ weeks that I had at least 1 female....nope, all 4 males. The duck (female) very distinctively quacks and the drake is raspy and sounds almost hoarse and can be hard to describe....but is NOT a quack.
It sounds like you have 1 duck and 2 drakes, but it could be more quacks are on the way...