Two of the four examples still use the gendered possessive pronoun 'his', so really don't illustrate the use of 'yo' for gender-indeterminate reference.
Really, the challenge isn't when a specific person of known gender is referenced, but when a person/role of unspecified gender needs to be referenced.
'Yo' is so close to the second-person pronoun 'you', and already used as a call-to-attention 'Yo!', that using it for third-person singular would be problematic.
"You should be detail-oriented, but your secretary must be detail-obsessed. Still, yo should be able to overlook minor errors by others."
Does 'yo' refer to the 'you' this is spoken to, or to the secretary? (A 'he' or 'she' or truly useful gender-indeterminate third-person-singular pronoun would be clear in that position.)
Really, the challenge isn't when a specific person of known gender is referenced, but when a person/role of unspecified gender needs to be referenced.
'Yo' is so close to the second-person pronoun 'you', and already used as a call-to-attention 'Yo!', that using it for third-person singular would be problematic.
"You should be detail-oriented, but your secretary must be detail-obsessed. Still, yo should be able to overlook minor errors by others."
Does 'yo' refer to the 'you' this is spoken to, or to the secretary? (A 'he' or 'she' or truly useful gender-indeterminate third-person-singular pronoun would be clear in that position.)