‘Kin’ is not a word for system member, fictive, soulbond, alter, or headmate. 

If you say your ‘kin’ or ‘kins’ to mean separate people from yourself who share your body/mind you are using the term incorrectly.

A kin, kintype, kinself, or fictotype always means the spiritual or mental identity of a singular person.

Headmates can have kintypes, but kintypes are not headmates.

A kintype/kinself is not a full person on its own, it is a spiritual or mental element of a person’s identity.