In fact...
... I argue that there is probably MORE ice on Mars today than the standard wet models permit. (Due to the details of how isotopic fractionation occurs in the atmosphere)
So far things are looking good. Odyssey has shifted the scales in my direction...
As for early Mars, you seem to have it mostly right there. I'm leaning on brief wet episodes in the Noachian followed by a dry Mars to the present day. Hard to adapt life to surface conditions, but not impossible...