Three brief items:
No main-belt asteroids are known that contain any significant amount of water - certainly not as ice.
Mars's former water likely is either 1) tied up in chemical combination in Mars's crust 2) frozen in the subsurface as ice and/or 3) dissociated to hydrogen and oxygen by ultraviolet light from the Sun and escaped off into space.
No living bacteria have been found in pristine meteorites, only in ones with a high likleyhood (how do you spell that word??) of contamination on the ground. The Martian meteorite "nannofossils" are still being debated, but look like they can be explained better by inorganic processes.