Not contradictory. The first group are people who got false positive test results. They got tested. The second group are people who got sick, think it was covid (but it wasn't), and recovered without ever getting tested.
Does data support you on (3) and (4)? I.e., if you had it and failed to generate a lasting response, does that mean a vaccine will have the same effect (i.e., won't generate a lasting immunity).
On 4, vaccine immunity may fade, but the vaccine will, by definition, occur after they've been infected. I've seen zero data to say that the previously infected who get vaxxed are in the same or a worse position than if they had not gotten vaxxed. Lots of data saying they're in a better position (see the recent CDC study looking at this issue with people in KY).