Stable mutagen should change names gradually.

[Klayboxx]

I don't think it's really possible for the game to figure out the difference between your first and last name. I'm fairly sure it sees your name as one solid thing.

from my basic knowledge of code it's really pretty simple to differentiate between parts of a string but whether or not it's feasible in byond is mystery to me

Well it'd probably be easy to change, but afaik names are just one big solid thing in this game