It's not just uncommon, it's unnatural.I know it's not common.
They are grammatically correct and you'd be understood. I'm not sure what you mean by "acceptable". While people might not say it to your face, they'll probably think to themselves that you don't know how to ask the question in a natural manner.But are the question and the answer grammatically correct and acceptable in formal settings?
I think the answer to "Are you married?" still is a simple "Yes" or "No." The problem is that "Are you married?" may not fully express what a questioner wants to know.The answer to 'Are you married?' is no longer simply 'Yes' or 'No'.
It could be 'I live with my partner in a civil relationship'.
I'm sorry, but 'contextually' this is far more complicated and 'general' means little or nothing.Can we ask someone, "what is your marital status?"? And can the answer be "My marital status is single."?
The context is general, neither formal nor informal.