The way I see it, everything except the point of present is probable: probable future and probable past. None of them are fixed.
Also, everything you know through your physical senses is your perception of the reality created by your own subconscious. This isn’t a perception of an objective reality that exists, but your perception of what your subconscious creates based on telepathic connections with everything else (not only humans).
So, coming back to your questions, whoever you meet now is your perception of somebody who exists in your current reality now. Any person you remember to have known is part of a probability your subconscious creates now, and it may not have a correspondence in their reality as you remember it.
By the way when you say “I”, “my”, and such you have to be careful what you mean (and I don’t say this in terms of wokeness), because you are somewhat different in each of the states of consciousness you experience (e.g. outer-self / ego, inner-self, dream-self, subconscious). The awake you, in most cases is your outer-self, but you may be more or less immersed in the physical reality created by your subconscious, and you can actually get into a dissociated trance and experience the physical reality from your inner-self’s perspective (e.g. you can see the physical reality without using your physical eyes).
In your second question / example (not sure how you contrast it with your first one), the fact that your acquaintance has died is part of a probable past your subconscious creates now. The acquaintance you remember may have not existed ever. If there is/was such a personality there is no way to say what he experienced in his reality. This is talking about common circumstances, because if you were evolved enough, you could to some degree project and experience anywhere in time / space / probability, even other previous incarnations of your entity, or incarnations of others.