I want to mention someone whom I know of only by references on the Internet such as forums and blogs(clarification: I want to write about the person, not to write to the person). This person uses a username of a woman’s first name with a lady’s photo as an avatar. Also, in some comments the person was referred as Ms by others.
Can I therefore by default use she/her/her/hers/herself for third-person pronouns when referencing this person, or should I instead use they/them/their/theirs/themself because this person is someone whom I have never myself met personally, but merely read about?
Is using words that have gender too personal for someone I haven’t actually met, like this person?
Is not using gender too impersonal for someone who to all appearances is female?
I hope that answers to this question will not be restricted by situations called out in the recent SE Code of Conduct “We also recommend that you don't make assumptions about people's gender and that you prefer gender-neutral language when unsure” (from https://meta.stackexchange.com/questions/336364/what-does-the-code-of-conduct-say-about-pronouns/336368#336368).
That’s because I am not asking anything at all about the SE Code of Conduct. I am just asking what the most common “preferred” usage in regular use is for this situation in present-day English from a common-sense point of view of a native speaker of English.
Clarification: I myself have a Russian-language background but have been living in Australia for more than 25 years. In all those years, I was somehow unaware of the so-called “singular they” construction until the very recent discussions about it on Meta. I was never taught about this construction when I was learning English, so I am unclear about when native speakers instinctively use it or avoid using it.