The bumblefoot I am familiar with but the bloating I am not. I have had 2 chicken hens with ascites but never a duck and their bellies were squishy, not hard.
Let's see if
@Isaac 0 is on.
For bumble, I soak for as many days as it takes to get the scab where I can easily peel it off without tearing good skin then I work on getting the infection out sometimes it comes out all at once with using a pair of sterile tweezers other times I have had to pick it out. Main thing is making sure it's all out then packing the hole with antibiotic salve and wrapping then checking every other day to make sure the infection is not forming again. Once your sure its all out let it stay wrapped till the skin has scabbed over. For soaking, you can use Epsom salt in the warm water just don't let her drink it because it's also a laxative.
For the bloating or whatever is going on. I hope some of these members I have tagged can help.
Any chance of getting her to a vet?