Yes spiritual gen would solve the problem of time better than "overlapping." Even "next gen" would because there will always be a next gen but Star Trek have already used it lol.
Interestingly, when I mentioned the "overlapping generation" to a "sister" recently she was very quick to point out latest to me the latest buzzword amongst the witnesses is the "era" not the "generation."
Some bright spark CO said it apparently and being good little sheeple they gobbled it up. I thought it shows how average dubs are struggling to hold on to the concept of "this generation" being "overlapping" so they invent a new word to make themselves feel better about it.