I’ll have to disagree with you on the Greek. No, I don’t know Greek, but others do.
One commentary says, “The verb ‘have been saved’ is in the perfect tense which expresses the present permanent state as a result of past action. Because believers have been ‘made alive’ spiritually with Christ, they have been and are saved.” - Bible Knowledge Commentary, NT, page 623
Young’s Literal Translation has it thus: “did make us to live together with the Christ, (by grace ye are having been saved,)” and “for by grace ye are having been saved, through faith, and this not of you — of God the gift,”.
That is consistent with the Vatican posted NAB: “But God, who is rich in mercy, because of the great love he had for us, even when we were dead in our transgressions, brought us to life with Christ (by grace you have been saved), raised us up with him, and seated us with him in the heavens in Christ Jesus...”.
You write, “I fail to see the logic that distinguishes all that are being saved and an individual convert. Isn’t an individual convert part of “all”?”
An individual is a part of all, but only a part. The all applies to...all. That includes me, and I was justified in 1971 - far in the future for Paul’s writing, but by 1972, I WAS justified. Or more precisely, I am in a present permanent state of salvation as the result of what happened in the past. And since the act that put me in a present permanent state was done by God, I’m not worried about it being undone by someone stronger in the future.
“Having been saved” is fine. The point is, it is the simplest grammatical form of Greek passive voice, which does not have all these English subtleties. It does not have a past perfect sense of “I had been saved” or “I was saved”. It is simply “I am saved”. It does not contradict your contention, but it does not support it textually.
We all agree that the Cross is a cardinal part of everyone’s justification and that is did occur in the past.
Surely if we speak collectively then there are people who were justified, who are being justified and who will be justified. This is true whether or not justification occurs at the time of death or at some time earlier. But the grammar of Romans 3 and Ephesians 2 is the same plain passive voice grammar, it is just that the translation you picked chose to translate the same grammatical structure two different ways. Why? Don’t get me started...