I definitely think that stand alone programs don't have much impact, as you say in point #3. In fact, evaluations that look at training alone find similar results for business profits to the normal microfinance literature: none. I did not want to include a training only arm here because the literature is pretty conclusive about the lack of effect for growing businesses from trainings. They do seem to have an effect though when paired with finance, which is consistent with other work I and others have done.
On filtering, its hard to say right now how to best target people, but I think charging for programs rarely brings those that need trainings the most, especially since the trainings take a significant amount of time for business owners, which is a major cost in itself.