Let's say, this is an issue of degree, rather than a black-and-white issue. For instance, if you have human DNA, rather than elephant or horse DNA, you can assume a human will come out.

If you can get an idea, will it be Asian, Caucasian, African,... — you can get therefrom a general idea, too.

But that is as far as it gets, sort of: humans look vastly different based on minor details. Think of actors in different roles. The closest you could get is a sort of "cohort" of possibilities for the looks.

Behavior, I trust, will be even less reliable.

An AI could "hallucinate" a "solution", sure, the way they "sharpen" images. But that would be A solution, not THE solution.