Just read through all of this so ideas are percolating.
Surprised no one has pointed out this potential thematic link between Mareep and the Nido family, namely that despite being related to Dragons (dinosaur-like for the Nidos, literally having Dragon blood in Mareep's case) they are in many ways the exact opposite of Dragons by being incredibly community oriented, highly sociable and easy to get along with.
In other words they are Family Mon, you know Mom-Friends, Papas, Good Eggs, the kind of Pokemon people dismiss because every civilian family has at least one acting as a HouseMon, this is what I propose our theme be. Now I know what your thinking, what's already been written about Joan clearly shows he hates HouseMon and can barely work with domestically bred Pokemon, as rebuttal I point to the fact he could tell that his families Houndoom had a spark of Wildness a few generations back and his general unease about Bugsy's Trainer-first methodology to propose that Joan doesn't hate Housemon he hates the wasted potential of a Pokemon that can only follow orders rather than help lead their allies to greater heights.
If we go with this theme the Housemon industry will have a very love-hate relationship with us, on the one hand we're drawing attention to the fact that the Family's Good Boy can make it in the Big Leagues (theoretically) on the other hand we just stole the highly empathic, perfectly even tempered Wild Mon that would have given their designer pet line just the shot in the arm it needed out from under them because we thought it would make an excellent battler (we were right of course)
As an added bonus this is one of the few proposed themes that is weighted towards some pokemon while still being able to have individual Pokemon fall into our theme, for example Nido"Queen don't need no man" and her progeny fall into our theme by nature of not being that far removed from what a Wild Nido usually is while "Steelix Mom whose got it going on" is unusually Mom-like for her line and probably has a few kids who have inherited that constructive rather than destructive instinct, meanwhile the "Rage Dragon" is even more opposed to this proposed aesthetic than the average Gyrados and should be avoided if possible. Though for those that still want to thumb their noses at the Dragon Clan we can always pick up a Dreepy once we've established ourselves, they're like Kangaskan but they don't need a Mega Stone to weaponize their Child Care.
Which leads to my next point, we're still developing a training style and we know that it will take a while to perfect so I propose a rather unique methodology based on the fact that we know Pokemon don't think like humans and if we follow my first proposal we'd be working with Pokemon for whom Child Rearing is highly important so why not use an Inhuman perspective by training our Pokemon so they can help train each other as a sort of "we all lift together" approach (I hear you like training Pokemon so I trained your Mon to train your Mon so they can train your Mon while your training mon)
Also, while a lot of people have proposed themes that I find intriguing their is a distinct lack of epithets being proposed, my contribution for my own proposal would be "Pillar of the Community" Joan.
Moving on from theming, I've really become enamored with the "Magnet Rise operated ballistic fluffball" proposal and have a potential solution for those worried what our fluffball will do once she becomes an Ampharos and has to rework her fighting style. I personally believe that a Marigold who makes extensive use of Magnet Rise will become even deadlierin the air as an Ampharos, using their mastery of electromagnetism to swim through the air and dance on an unseen wind.
In fact I propose something more extreme, multiple canons have been incorporated into this quest so somewhere there must be a Surfing Pikachu so let's aim for the heavens and have Marigold be our designated Flyer, sure it would probably be beyond her until she's an Ampharos but Flying is usually late game enough that Marigold should get their right around the time we'd be getting it in game
and their those are my ideas, what do you think
ReverendSwing and everyone else is FamilyMon/Opposite of Dragons a good theme and can we potentially fly on Ampharosback or are these just pipe dreams
edit: sorry is that better, not used to having extensive ideas that don't have glaringly obvious cutoff points, will happily take suggestions for improved readability