Well... the guideline for us so far has been that any time you get to the end point of a challenge in one save file, that should count separately. The Game Mastery challenge can be divided into a lot of single challenge runs anyways, right? However, given that the forum migration is happening soon - which will bring about a totally new badges system in the place of this one - and that there are (admittedly) some things I'd need to go through with the current Challenge Badges, it's probably better if we deal with all of this after the migration... sorry for that and thanks for the understanding ♥
Sorry for lateness. Got hit wit IRL (and alas, will be still for a while) but got back to your PM. The tl;dr is I don't see glaring issues and there's only one part I'd suggest you ask another mod about, the rest seems to be fine.
The rules as posted are current, there's not really been much need to adapt them further; ofc, Pokécommunity's general rules also apply.
So long as the cursing and the humor doesn't cross into the particulars posted in the thread there shouldn't be much issue. As a general rule, remember that since this site is accessed by a general public, if your story touches upon anything that goes past K+ rating it *probably* needs warnings; if it touches upon stuff that goes above T, *definitively* needs warnings. Cursing and that kind of stuff can be used sparingly. Mindful of what counts as "middle school" humor since that can get touchy on aspects such as hazing and bullying, which *absolutely* need a warning. When in doubt: as the thread says, you can PM a mod with a sample of writing, for example.
Actually, after sending my answer and talking about it with other Challenges mod, we figured out even better solution. You could start in the thread I sent you, but then post actual updates in Travel Journals, where they will have better visibility.