She/her covers 3 of the 4 you mention, and the fourth form always ends in an s. So it's not really necessary to hit all 4 in a signature line.

Additionally, the common pronouns (he, she, they) only really need a mechanism to tell a speaker which set to use - "he/his" is a label for a set, not the set itself.

For neo pronouns, I agree, it's probably best to lay them all out to reduce ambiguity.

the point of doing it for non-neopronouns is to have neopronouns be less of an exception.

> he/his" is a label for a set, not the set itself.

I did not think of this. It makes a lot of sense.