Apparently there is a way to change the Mew glitch using a Pokémon spec stat or something in Blue while performing the Mew glitch to obtain mewtwo? Will I be able to transfer this Mewtwo to SM/USUM?
With the help of this map, you can see all the different Pokemon encounterable with the Mew glitch. Now, I'm not certain if any enemy trainers have a Pokemon with a Special stat of 131, but if you can get a Pokemon with that stat, you can encounter a wild Ditto and have it transform into that, and then perform the glitch as usual.
I believe it can be transferred to SM/USUM, and I'm not certain about this but you might have to get it above level 70 for it, considering that Mews glitched with the correct OT and ID won't transfer if they're below level 5.
Edit: removed incorrect information