I'll start with the easier part of this question, "what counts as interaction". If any of the following are true, you're fine to use she/her for me:
• We know each other outside of Cohost
(whether offline or elsewhere online) and/OR
• We have spoken directly to each other
(whether verbal or written)
(back and forth comments in a reply thread do count for this)
(one of us chatting in the other's stream also counts) and/OR
• We follow each other here or on any form of website (asynchronous counts; if I follow you on Cohost and you follow me on Twitch, that counts)
There's no time limit on this; if we met 20 years ago but haven't talked in 10, you're fine to use she/her.
Probably other versions of this are true as well, these are just the 3 simplest ways I could think to categorize them atm.
The basic idea is that if you have any idea of who I am as a person, and I have any way of purposely recognizing you, you can use she/her for me. If you have questions, please ask!
A couple examples of what would NOT count as interaction:
• hatereading or hatefollowing me
• using my content on an aggregator site
I know neither of those cases are well-known for being particularly respectful of one's pronouns, but hey, just in case.
A couple possibly respectful examples:
• responding about me in someone's thread where we don't know each other
• talking with someone who does interact with me about me
Those in the respectful noninteracting group switch to interacting once interaction happens.
The harder question to answer: why "none"?
tl;dr: I don't like when people I don't know in any way and who don't know me in any way use she/her to refer to me online. I'm not comfortable with them using other pronouns for me, either. The exception is, if someone doesn't know and hasn't looked it up, they can use they/them in the same way anyone can when you don't know what a person's pronouns are. Otherwise, I would prefer for this group of people to use my name only unless/until we do interact, at which point I'm fine with she/her.
Every time I do a gender check-in it comes up extremely cis, but choosing to separate my pronouns in this way is mostly my attempt to reflect my culture, and in some ways, how it informs my identity, especially online. The way I'm using the concept isn't a one-to-one translation, and it's not meant to be. A lot (probably 99%+) of other Vietnamese people do not do this and will probably disagree with what I've said here and that's okay.
Cut for the aforementioned "tl" part which involves family stories and Vietnamese language and culture:
When I was growing up, I vividly remember my Bà Ngoại refusing to let "she" be the pronoun people used. This was not because of trans reasons but because of translation reasons.
Vietnamese pronouns are almost entirely familial/relational; for example, the words for "Mr." and "Mrs." (or "man" and "woman") are ones you would also use as a short form for addressing your grandparents. We have some professional titles which can also be used as pronouns much as they are in English (such as "Professor" or "Doctor"). You can also refer to people that you don't know, or know casually, or can speak to informally, by their name (even when addressing them to their face). There's more but it's beside the point.
Anyway, there is a translation for she/her/he/him/it/it/they/them, and I say the pronouns like that because it's one word that covers all of them, nó. However, if I were to translate a text, I most likely wouldn't use nó and would either find the appropriate relational pronoun or use the person's name. In my family, nó is mostly used for babies, children, pets, vague entities, when telling stories about people you don't know or aren't close with, that sort of thing. It would be…okay to use it when referring to friends if the friends were comfortable with that, but more often friends will refer to each other using familial/relational pronouns or by first name. (Ironic tangent: the word for "friend" is often used in language learning apps as the word for "you" since we don't really have another polite form of it. However if you only ever use "bạn" with someone it's usually a sign y'all aren't close 😂) The reason my Bà Ngoại did not like "she" is because, the way Bà initially understood the translation, it was translated in a way that felt dismissive of the close relationship we have as a family.
The way I used to put it was "don't use pronouns for me like you know me. But if you do know me, she/her." This was a very glib and unnuanced description mainly optimized for character limits and is replaced by the description and explanation in this post.