This is fascinating. So you know that you've met someone before. You know things about them. But you don't recognize them? What does this mean? You don't remember their name? You don't know why or how you know them?
I'm not the OP neither have their problem, but I can't remember names. I know who the person in front of me is, we can talk pleasantly about everything - I have a good memory otherwise - but I can't remember their name to save my life. Luckily they very seldom notice that, if ever. And I won't tell, obviously.
I'm similar, and yes, there are easy options to replace person's name with, as long as you're putting a bit of thought into what you're saying so as not to paint yourself into a name corner.
Ironically, I'm insanely good at remembering faces. But it's kinda useless because of the name thing (and equally, the face context is also difficult).
A trick helping momentarily is introducing them to another person. Then I pick up their name from the conversation and can use it myself - at least for 10 minutes until I forget it again.
"Hi there, I'm ABC, nice to meet you, what's your name"
"...Huh? I'm XYZ. We've met before."
"Oh right...sorry, I promise I remember you! We knew each other from there, and we've worked on this and that together, and etc. etc. etc. I'm just terrible with faces, I'm so sorry!"
It's not "you know things about them without recognizing them"; it's "you don't recognize them at first, it gets awkward, and so you recite facts about them prove that you didn't forget who they were"
My aunt said tells neighbors/acquaintances to just introduce themselves by name every time when they start chatting with her, and reports great success with this — but my entire family is also rather 'take it or leave it' re: social stuff, so the people that don't introduce themselves don't get remembered, which seems perfectly fair.
That I don't know if they're a stranger or not. I introduce myself to acquaintances fairly regularly (sometimes annoying them that I apparently think they're so unmemorable) because I'm the opposite of 'I never forget a face'.
I think normal people are more likely to have the experience where they can't remember a name and why/how/where they know someone from. I of course forget things like anyone, but that's unrelated.