It is inherently a duplicate. As mentioned the particular example is different but past perfect progressive vs past simple doesn't make any difference.
However, there might be some things to add, particularly since you fleshed out your question nicely with two more and as we are talking about a progressive case, shades of continuity can creep in more so.
Both can be used but there are nuances that might shade your leaning towards a particular one. I'd contend "last" connotates some likelihood that the seven year membership might be up (or that there is some suspicion on the part of the speaker that it may be up), whereas "past" makes this possibility less likely. Another connotation is that "last" is more likely than "past" to be identified with stricter calendar boundaries (if stating "financial years" e.g., last is more commonly used).