I’m generally not huge on boys names for girls, although I have soft spots for Dylan, Austen, Harper, and Reese as middle names. I follow your logic on softening up masculine names, I just tend to choose feminine first names with masculine/unisex middle names. But I think fielder is cute. It does feel a little masculine, but you can totally get away with it. I really like Fielder Wren Marin, but Fielder Grace Marin feels much more feminine to me, so I’d probably go with that one if I were you. It soften the name up a bit. I think some great alternatives to Fielder would be-
Harper -I know it’s trendy, but I think it’s a great name. And Harper Wren would be SO cool with the To Kill a Mockingbird association.
Sawyer -my lit-geek shows herself yet again, but I think Sawyer is also an awesome name. And Sawyer Grace Marin is GORGEOUS.
Piper - It’s cute, fun and spunky. And I really like Piper Wren.
Jude -I like Jude on a girl. Jude Wren Marin doesn’t work for me, but Jude Grace Marin is cute, and I’m sure you could come up with some other awesome options. I like Jude Elizabeth Marin. Dawson, Addison, and Jude really works for me.
Monroe -I know Mariah Carey kind of tainted it this year, but I think Monroe is a lovely unisex choice that works well with your sib set.
Elliot or Ellington or Ellison - I think these are both great choices with AMAZING nickname potential. Elle, Elli, Ella…it’s endless adorableness.
Hallie (pronounced Hal-ee)- I think Hallie is a lovely, underused classic. It looks so clean and soft when written and it just has a great sound about it. And Hallie Wren is devine.
Edith -I know it takes your list in a really opposite direction, but I just LOVE the idea of Dawson, Addison, and Edith, so I have to throw it out there.
Sloane -It just looks so sleek and lovely. I think it’s a great name. Not overly feminine or overly masculine. It’s just a beautiful name.
Madeline -I just love it with your sib set. Great nickname potential. Sweet, soft name. I can’t help but love it.
Hudson -It’s pretty masculine, but I think it works nicely with your sib set. DawSON, AddiSON, HudSON. And Hudson Grace is stunning!!!
Emerson -Also works great with the SON theme in your sib set. And I think Emme, Emmie, Em, are great nickname options. And I just have to throw out Emerson Iris Marin, cause I think it’s fabulous.
Owen -I know it’s a boys name, but I think it adorable on a girl. Owen Elizabeth Marin is to die for. And Owen Grace is so sweet. I love it!
Georgia -I know I’m going way off on this one, but I LOVE Georgia Wren. It just feels SO perfect. I can’t pass up suggesting it.
Good luck!