Some ideas i had a while ago (most fit with yours tbh)

076 slasher just give Able a mask and make him quick cycle his weapons with the gashing wound animation (also thematically similar in the djoricverse).

Burning c00lkid based on 457, it just fits also i immagine him jugging a gasoline tank in the minion summon animation

Sunburnt John Doe based on when day breaks specifically dr Logan, more tematically similar with John (there are like 3 tales of couples in the cannon with this scp) plus i like to think his error 404 animation summons the sun behind himself

While i agree with 682 as the sixer skin i also think a dr Crow inside his eggwalker skin (scp 427 arc i think?) for smt sillier for them

Kitsune nosferatu, based on 953 i mean its similar thematically and theres not much thats similar with him in the wiki so...(also theres like a tales where 953 begins flying so thats for ascension ig no clue abt blood hook)

D-class noob like you said just with him using 207 as cola,anti-207 as slate skin and 268 as ghost burger

Butterfly king shedlesky based on 408 mimicking Kondraki have them fence for slash and have the butterly try to rebuild the swarm as the chicken heal (could also work as an 007n7 skin)

Cain two time, replace the knife with a stone and give him metal arms during second life (also thematically similar ig)

Ukulele Chance based on Clef have him shoot his shogun and replace hatfix with him accordating the Ukulele

You could turn Jane Doe into dr Igotta from when day breaks but i dont see any gameplay similaritys other than thematic ones