Curate, connect, and discover
So I had speculated before that when Ingo was transported to Hisui, because they're two of the prizes that you can buy in any incarnation of the Battle Subway, it's not a stretch of the imagination to think that Ingo may have had a Razor Fang and Razor Claw on him. And if this is true, then it's entirely possible that he was the person responsible for Lady Sneasler becoming... Well... A Sneasler. If he was responsible for her evolution, it would certainly explain why Ingo was allowed to become a Warden in spite of being an outsider to the Pearl Clan when they seem to have a distrust of strangers.
But thinking about it... Actually... Maybe every Warden has a deep tie to their ward like that. We obviously see that Palina was at least partially responsible for Growlithe evolving into Lord Arcanine. (Without a Fire Stone to boot!) But it would also absolutely make sense that Lian would have dug up some Black Augurite which was later used to evolve Scyther into Lord Kleavor!
The more I think about it, really the more it kinda just feels right that maybe the Wardens were selected at least in part because they played a role in their wards evolving and fully taking on their roles as Noble/Ride Pokemon. It would certainly help to explain the more odd choices the clans have made in deciding who becomes a Warden. Sabi being the one to level Braviary up until it evolved would certainly explain her weirdly OP team! And Gaeric is obviously the kind of person who would have leveled up Lord Avalugg. Perhaps Wyrdeer and Basculegion were trying to protect Mai and Iscan respectively when they evolved. And maybe Calaba had been collecting peat for medicinal/ceremonial purposes under the light of a full moon. I don't know what Melli and Arezu would have done to get their wards to evolve... Lian clearly has an interest in rocks, so it only make sense for him to have dug up some Black Augurite, but that doesn't really feel like that would have been the case for Arezu finding a Sun Stone and Melli finding a Leaf Stone. There might be a story there, but I don't know what it would be. The best that I've got is that in Platinum, both can be found in the areas that were once the Crimson Mirelands, so maybe those are just areas where those stones exist in relative abundance and can be found? Who knows? Fun to think about though!