Respondents: 29 (This poll is closed)
Also, I do not like [name_f]Guinevere[/name_f], [name_f]Gwendolen[/name_f], or any other “[name_f]Gwen[/name_f]” name. Thank you!
Maybe it’s my southern accent, but [name_f]Gwen[/name_f] and [name_u]Gwin[/name_u] are the same to me. So are pin and pen. I’ll really confuse a little more and suggest [name_f]Gwyneth[/name_f] [name_f]Susannah[/name_f]. I usually advise naming the child what she will be called, but since your other kids have a longer name with a nn, I err on that side. So [name_f]Gwyneth[/name_f] is a great choice, and I highly prefer [name_f]Susannah[/name_f] over [name_f]Maren[/name_f].
A name that I love is [name_f]Gwendolen[/name_f]/[name_f]Gwendolyn[/name_f] nn [name_f]Gwen[/name_f]. Maybe that is an option for you. 
I want to vote for [name_f]Gwenyth[/name_f] [name_f]Susannah[/name_f]!
Thank you for this feedback! My name is [name_f]Susannah[/name_f] so I don’t love that for a middle but it was the only one I thought went with one syllable “[name_f]Gwen[/name_f]”. [name_f]Maren[/name_f] is my moms name and my mother in laws name combined.
I thought [name_f]Gwen[/name_f] and [name_u]Gwyn[/name_u] were pronounced similarly as well but I’m reading otherwise. I welcome more feedback!
[name_f]Gwyneth[/name_f] is definitely pronounced with the “gwin” sound, but I don’t think that means her nickname can’t be [name_f]Gwen[/name_f]! Americans are much more familiar with [name_f]Gwen[/name_f] than with [name_u]Gwin[/name_u] and I can imagine that little kids will automatically say [name_f]Gwen[/name_f]. I know a little girl named [name_f]Gwyneth[/name_f] and half the time people say [name_f]Gwen[/name_f], half [name_u]Gwin[/name_u]. I think it has more to do with people’s personal pronounciations and accents than the actual name.
What about [name_f]Gwendolen[/name_f] nn [name_f]Gwen[/name_f]? Maybe [name_f]Gwendolen[/name_f] [name_f]Maeve[/name_f] or [name_f]Gwendolen[/name_f] [name_f]Susannah[/name_f] as full names with [name_f]Gwen[/name_f] as a nn?
Personally I think [name_f]Gwen[/name_f] is a fine nickname for [name_f]Gwyneth[/name_f]. But if you are uncomfortable with that, my vote is for [name_f]Gwenyth[/name_f] [name_f]Maren[/name_f]. [name_m]Just[/name_m] as lovely, gives you the nickname you prefer and the middle you prefer to use to honor the grandmothers. Best of luck!