So, if the passage from 2:8-14 is entirely focused on modesty and prudence, and Paul's only opposed to one-on-one discipleship as far as women teaching is concerned, what's up with "she will be saved by childbirth"? I'm not sure, but I'm going to try building on the question I asked at the end of post #2: "Is Paul partly suggesting the tragedy of a one-on-one problem can find salvation through multiplication?"
One problem in the Garden of Eden was that the snake caught the duo before they had multiplied. Worse yet, the snake probably caught Eve alone. (Adam does not appear from Gen.3:1-5a.) Like Solomon said that many counselors contain wisdom, Paul said the church is held together from that which every joint supplies (Eph.4). Paul, of course, also knew that the snake caught Eve alone, and that her disobedience spread to Adam. This illustrates that a one-on-one situation is not only dangerous because of male/female intimacy issues. A one-on-one partnership is also dangerous because there is less safety for a duo, on many levels, than there is with a larger community.
From that perspective, we should realize that part of childbearing is multiplying, and that a key advantage of growing in number is being able to pluralize corporate functioning.
Now then, I don't know how Paul understood v.15, or if he really meant to imply that the churches' behavior might be somehow "saving" or "preserving" our great grandmother Eve. I'm certainly not speculating on Eve's eternal destiny one way or the other. I will, however, suggest that Paul must have noticed how God (in the Old Testament) kept on calling the nation of Israel "Jacob" for hundreds of years. I can also attest my children's grandparents have seen many ancestors in their sweet little faces. In some sense, we may all "preserve" Eve in some respect, and perhaps all the more so when we live up to what God planned for Eve (and for Adam) to do.
Verse 15 may or may not be that deep. But the grammar seems clear. The implied "she" is singular and so the implied "they" should logically refer EITHER to Adam & Eve as a couple OR to the fruits of their childbearing, their descendants. I find the second to be more likely because of the future tense verb.
I won't speculate further on Paul's bizarre theological tangent, except to emphasize once again that - whatever else is going on here - the progression of thought shows that Eve's singular fall is somehow, at least partly redeemed by the multiplication of her own company. Beyond that , Eve's seed (via Abraham, according to Paul in Galatians) eventually produced Christ, in whom the whole Body is held together, and in whom we fulfill God's original purpose for Adam & Eve, on Earth.
Perhaps Paul is only saying that Eve took care of the multiplying, and now we (in Christ) have to finish the rest. Whatever he means, the theological implications still appear to be some kind of tangent. The shift from singular back into plural marks a turning point for Paul's thoughts in the letter.
My own bottom line: Whether or not my attempts to explain this shift are all valid, we must note that it corresponds with the natural pluralization of childbirth. As I said in post #2, that observation could very well change the whole view of who "she" and "they" might be.
There are still questions, of course, but the potential significance demands further attention.
To be concluded...