I lean towards leaving the parent set to "ones you wont hear in sunday school", but think it should also have a link to and from both tropes pages you mentioned. In general, more connections is a good thing, as it makes random free-form browsing and brainstorming easier.
For the record, we already have several instances of things listed on arcanawiki as tropes that aren't on the TV Tropes site, and I think that's just fine. Most are specific to gaming, such as RPG terminology or common things that players do. I can think of at least one or two pages specific to time-travel games, for instance, that cover things that players always do when you give them a time machine, but characters in fiction and movies never do. So, whether or not it's listed on the TV Tropes site is not always the best guide for us. Sometimes our needs are just different than theirs.
