re: We work from what we know to what we can imagine (unless we are writing SF).
If life exists on Mars and it has evolved from a wet world to a very very very dry one I'm sure it does all you say it could. But, you are not the first person to suggest this. Martian life has a long history within human minds. Bob Clark and others here and elsewhere have suggested Mars has possible water and life.
Anyway, I see here (on the only data point we have) bacteria that survive without much water, lives in acid easily, thrives under UV and loves hard radiation, but non of these are the very same bacteria. Evolution gave us winds and legs I could imagine your life forms existing and have time to time played devils advocate for multi celled life there, but I prefer to fence sit (after all I'm no biologist).