archaebacteria

Carl Woese - Discoverer of the 3rd domain of life archaebacteria among other scientific accomplishments.

All of biological evolution from archaebacteria to humans was required to get to human.

They are known to be the most common archaebacteria in deep subterranean habitats.

Life would never have risen above the level of archaebacteria, if at all.

For example, there is an archaebacteria (the exact name of which escapes me at this moment) that is critical for providing bioavailable nitrogen on very young volcanic islands.

(And that was with detailed instructions!) Bottom line: figuring out growth conditions for novel species is hard, especially with the relatively mysterious archaebacteria.

But what of total biostasis, preserving the entire organism, just like the archaebacteria that live for thousands of years in ice or other extreme environments by slowing their metabolisms to a crawl?

The idea of multicellular life on Ceres is implausible for the reasons you mentioned, but there could be something like archaebacteria or other extremophiles with very slow metabolisms and which don't reproduce very often.

There are at least half a dozen research groups trying to force this archaebacteria to evolve to a point where it can carry out nitrogen fixation in the presence of oxygen while doing it at a much lower temperature than it evolved for, which is roughly 100° C.