Is there ever going to be a story with both Sam and Dean normal size with a tiny?
We actually do have a few planned out in the BA multiverse!
Brothers Chosen will have canon Sam and Dean discovering cursed Stan Baker the captive of a he-witch they’re hunting, and will have to figure out what to do with this tiny ginger after the case is over.
There’s plans for Jacob to be besieged by the canon-sized Sam and Dean, though this idea is only in the planning stages currently, and may change wildly when we begin writing it.
Brothers United pairs tiny Oscar with the weechesters, and will have a very different outcome than Brothers Together did when they were kids… This will be a lot of canon bros growing up with tiny Oscar!
Outside of the BA Multiverse, there’s also Neon’s story Beggars Can’t be Choosers, which involves the Canon Winchesters finding none other than little Oscar in their motel room. It’s from the Angel and the Mouse AU, which began with Quiet as a Mouse (with Castiel, Angel of the Lord, finding Oscar).