A non-believing friend counters the idea of a creationist God by contending for seeding from aliens. I realize this idea is preposterous to you, but I didn’t find anything specifically on this at your website or in you evidences materials that explains your thinking. Any ideas?

Actually I believe it is possible God used seeding, just as he used supernovas to distribute the heavier elements throughout the universe to prepare conditions for the eventual presence of life. But if true this only pushes back the question of why our world exists and other creation-related questions.

If there was life somewhere else, how did that come to be? Who created the aliens? I suppose your friend could say that they too were seeded from elsewhere. Maybe so, but the creation questions remain. When Richard Dawkins made his seeding suggestion in his dialogue with Alister McGrath, he wasn't really offering an explanation at all. The more aliens one posits, the more things there are to explain!

For more, you might take a look at the bibliography of Compelling for reading suggestions.