Poetry can be challenging to read, especially because poems often have multiple meanings. I'll put forward my interpretation of that line, and I welcome others to share their thoughts as well.
You're absolutely correct that the author is basically saying:
We never heard where they went or whether they were still alive.
The meaning of the word "mock", however, I think is somewhat complicated. I see a couple of interpretations, and I think the author may have meant a little of each:
First Interpreation
The word "mock" very literally means "treat with contempt or ridicule". The soldiers who are still alive have found the experience of war to be so awful that they now talk about their contempt for the support they received from the women.
Second Interpretation
The word "mock" still means "treat with contempt or ridicule", but less literally. The soldiers are not actually talking amongst themselves. Rather, war is so awful that the mere fact that they must serve as soldiers in a terrible war shows contempt for the love and affection they were shown when leaving the town.
Third Interpretation
The word "mock" means "disappoint or frustrate (the hopes of)". In this interpretation, the fact that the soldiers must fight in a war frustrates the hopes of the women who wished only the best for the soldiers leaving the town.
Conclusion
I think the author may have meant a little of each of these interpretations. I don't believe he meant that the soldiers were laughing and joking about the flowers, however, since that doesn't match the somber mood of the rest of the poem.
It is (often) an emphatic form.
So, tell me, Mrs Jones, about this son of yours! I hear he's an accomplished singer, mathematician, and painter.
This ol' heart of mine has been skipping a few beats lately, doc.
She'd better start cleaning up after that dog of hers!
"ole" or "ol'" = "old" (so-called "eye-dialect").
Best Answer
Yes, they have the same meaning - also "Which one is your husband?"
Who among them is not very idiomatic for identifying an individual. You might use it for asking whether something applies to any member(s) of a group.