Langers, I'm not entirely sure what you mean here. Can you be more specific or more detailed?
For example, when you say you "are left with an empty adgroup (which I also cannot remove)", I don't really know what you mean.
And when you say "validate creatives" do you actually mean review and approve creatives?
By "invalid creative" do you mean an ad that turns out not to be approved?
I'd be happy to pass your query by my AdWords API colleague, but I need to understand your questions more fully if possible.
My best guess, based on my understanding of your question is that the answer will be no. There is not a way that I'm aware of to have ads pre-reviewed and pre-approved. BTW, it's not just the ad that gets reviewed, but the ad, it's keywords, and the site that it links to.