Two questions about a StoryOrigin promo

First, I’m looking into doing story origin promo that i could feature my reader magnet in. However, does my reader magnet have to be on Kindle Unlimited for it work? I was looking through the group promos and they’re almost all either a giveaway, Kindle Unlimited, or a sale. Considering my short story is free I don’t find the giveaway or sale options needed or enticing. Any thoughts?

Second, would anyone be interested in participating in a Christian thriller/action StoryOrigin Promo? Especially (but not exclusively) targeting men readers?