If the goal is to seed life, why not send something already alive instead? Though I don't think we know what to send that would be a living colony still by the time it arrived, even if we knew how to send it exactly. And it'd probably just die when it arrived unless we get a much better idea of what's there already.

An artificial intelligence would likely be the best bet actually, but there's a bunch of challenges there we don't actually know how to solve either. Maybe in a few decades there will be fewer unknowns at least.