I would say … you would have to look up the web for why Firefox is called Firefox but the other three are intentional pisstake names that are derived from and intentionally referencing Firefox (all three are forks of Firefox).
So, if none of those 4 browsers floats your boat, you too can fork Firefox - and while it is building from source, you can think about what word to replace “fire” with and what word to replace “fox” with. I will go with FlyingKangaroo but if my fork doesn’t work well maybe DeadDingo.
Forgotten to answer. I mean nothing, because IceWeasel was mentioned by the person I answered to. But I did not think about IceCat and still I cannot give an answer to it.