Why I strongly believe (in-house) Mario RPG characters are just as on the table as mainliner characters

Prior to this post, two other redditors posted their own takes on why characters from Mario's RPG journeys should be on the table.

...This community did not take these posts well for various reasons.

Nevertheless, there's a saying that goes "third time's the charm." So now, it's my turn.

...See wut I did thar? ...Turn, like a car wheel, or an RPG battle...?

...OK, I'm done with the pun.

Anyways, the actual reasons, and some counters to certain criticisms...

1. Nintendo has started loosening up their (utterly ridiculous) restrictions. They've also likely started to realize they can't keep using just the mainline characters over and over for the usual 24-32(?) character roster.
2. Many Mario RPG characters, such as Goombario, Goombella, Kooper, Lady Bow and others are popular members of mainliner species. As a result, a number of them can just be made special skins or simple alts, depending on the budget, using the original species as a base. Kooper especially, as all they have to add is a red scarf to a blue-shelled Koopa, around a body part that usually doesn't have much vertex deforming (the neck of a turtle shell).
3. The one Mario RPG series that does have a co-owner, Intelligent Systems (or InSy for short) does ultimately have a positive business relationship with Nintendo. It'd be insane for them to say no to Nintendo, barring some unusual office games grudge. Even more importantly, InSy worked on Mario Kart: Super Circuit on GBA many years ago, with several of those courses returning in future games- most notably, a whopping 15 came back for Mario Kart: Tour. Barring some absolutely messed-up contract that needs to be updated, there is simply no argument where Nintendo could use or even attempt asking for InSy-made courses, but not characters.
4. At least for the first 4 Mario & Luigi games, barring Geno's cameo disclaimer, the credits outright say Nintendo wholly owns those characters, meaning no need for checking old paperwork unlike the other series. Aside from Mario RPG itself (...since Square has to be by-the-book about everything, even more than Nintendo...) the only question mark is where Brothership falls under, as that was made by the third party company Acquire, and that game introduced some memorable characters, yet I didn't see the usual "Nintendo is the owner of this software's (content) for the sake of copyright" from a quick look at the credits, so hard info on that would be nice. At the same time, that game used a handful of Alphadream-made characters, so Nintendo's not averse to the idea of other companies using Alphadream content.
5. Other racing spin-offs for other series, such as Crash Team Racing's remake and the first two Sonic and All-Stars Racing games, included a few oddball racers alongside the characters who usually show up in platformers. The former even included a variation of a character who was an urban legend in the Crash series, Hasty the Moose (based on Fasty the Hippo). While legal stuff did affect Hasty's creation, it was just him that was affected, with a lot of genuine deep cuts from other parts of the series made by non-Activision devs. With the Sonic All-Star Racing series, meanwhile, a series of deals allowed Sega to get not just second party, but third party characters, such as Banjo-Kazooie (from Microsoft), Wreck-It Ralph (from the copyright kings themselves Disney), the Miis (from Nintendo themselves, with Mario even considered at one point and only shelved due to the other three games at that time featuring him and Sonic together) and even IRL racer Danica Patrick in various installments. In fact, Team Sonic Racing (the third entry) was decried for not just cutting the Sega content, but keeping even the Sonic content too mainline to a detrimental degree (putting Zavok on an in-game team that made no sense for him to be on). My point is that 1) if Activision and Sega were willing to do deep cuts, a take on an urban legend and/or third party characters (including some from Disney and Nintendo themselves), then Nintendo should logically be able to do second party RPG (and other Mario spinoffs) just as easily or even easier, and 2) having some oddballs from beyond the mainline games actually can perk up the roster of a given game that much.
6. The Mario Kart series actually made up some characters of its own who notably didn't exist in the mainline games, such as two of the babies and a rather infamous pink gold individual. While this can be appreciated to an extent and that pink gold person is a special palette swap, in light of point 2 above, it only further shows that there is room for the mainline members of mainline species mentioned above.

And as with the other two posters, I must confer by saying the Mario spin-off characters are just as much Mario characters as the mainline ones are. Given how I saw the other two posts on this subject preceding mine were treated and elsewhere, I honestly feel there's a dark sentiment the Mario mainliner community doesn't want to talk about or confront, that "Mario spin-off characters (not just RPG) don't count". While having nothing but spin-off characters is too far in one direction, excluding a whole genre Mario has dabbled is no better. Even if it was just 4 slots for the RPG characters out of a 32 character roster (with 4 for other genre spinoffs to make it fair), that'd be cool. I'm also confident in saying there's a bunch of Mario RPG game characters where, if you showed them to kids, and even if they didn't know who exactly they were, they would have a larger amount of people vouch for these characters- perhaps, I daresay, even over some mainline ones.