I can buy antmen being less bright than dwarves, but unless they're digging with their jaws they wouldn't necessarily be faster diggers than dwarves. And how would frogmens' tounges help their fishing, and since even larger frogs IRL don't survive on nothing but bugs why would larger frogmen?
So? If dwarves could eat tattered clothes it would reduce the refuse piles needed but that doesn't make sense.
You have misunderstood me several times. I said that frogmen who work for your dwarves could help clear up fly swarms. I did not say that would help them with their fishing. Some frogs are known to eat small fish too, but it's rare. That's why I started talking about amphibian men who are a bit more ambiguous. I suppose though, frogmen could still fish pretty well, it's not like they'd want to eat them though. The reason why is that they're amphibious and could stay in the water for extended periods of time, unlike your dwarves. You'd be better off using them as aquatic haulers or scouts or something though. Guards for your underwater fortress.
Furthermore, my image of an antman is of a creature without much brains, unbreakable loyalty to its queen and an insane work ethic. They would work harder than the most assiduous dwarf, and could dig with greater efficiency owing to their natural strength (remember how strong ants are) and agility. If you struggle to understand what I'm trying to say here, if you ever see ants going about their business, they're almost mechanical. Think of how a spider or similar arthropod operates in a way that's almost mechanical to our eyes, but is just a product of a brain utterly dedicated to what it's doing. Now do you see why antmen could dig faster than a dwarf? The comment about the refuse piles is also frivolous and has no bearing here.
I'm suggesting that the difference between antmen and dwarves is that antmen are diggers, dwarves are miners. Antmen can dig really quickly and efficiently, dwarves mine; they dig more slowly, but produce more stone. If you want to reduce the amount of stone you are going to end up with, like if you have to mine a 20x20 room full of gabbro, use antmen. Antmen would also be unable to smooth and decorate stone, for they are coarse and unenlightened folk.