[name_m]Jullian[/name_m] Maebry is lovely.
Oh no! Well, do you want to name after your mom? You really shouldn’t have to feel “obligated,” but I understand how family can be! It might be easier to just not use a family name at all.
If you decide you’d like to use [name_f]Leah[/name_f], you wouldn’t have to use that name alone, as there are lots of names that have a “lia” sound in them, such as:
[name_f]Amelia[/name_f]
[name_f]Aaliyah[/name_f]
[name_f]Aurelia[/name_f]
[name_f]Azalea[/name_f]
[name_f]Cecelia[/name_f]
[name_f]Celia[/name_f]
[name_f]Clia[/name_f]
[name_f]Cordelia[/name_f]
[name_f]Cornelia[/name_f]
[name_f]Dahlia[/name_f]
[name_f]Delia[/name_f]
[name_f]Ellia[/name_f]
[name_f]Elianore[/name_f]
[name_f]Emilia[/name_f]
[name_f]Evangelia[/name_f]
[name_f]Gallia[/name_f]
[name_f]Julia[/name_f] (isn’t this on your list now?)
[name_f]Kylia[/name_f]
[name_f]Magnolia[/name_f]
[name_f]Malia[/name_f]
[name_f]Nellia[/name_f]
[name_f]Natalia[/name_f]
[name_f]Odelia[/name_f]
[name_f]Rosalia[/name_f]
[name_f]Zelia[/name_f]
Technically, [name_f]Jillian[/name_f] has a “leah” sound in it. Maybe why your mom thought of mentioning her middle name in the first place?
My daughter’s name is [name_f]Jillian[/name_f]. I struggled so so much to choose her name, but now that she is [name_f]Jillian[/name_f] I absolutely love it and I don’t know how I will ever be able to choose a name for our 2nd daughter that I could love as much as [name_f]Jillian[/name_f]'s. She is usually always called [name_f]Jillian[/name_f], and it has never really been shortened to [name_f]Jill[/name_f] by anyone. Ocassionally we’ll call her [name_f]Jilly[/name_f] at home. I love how everyone is immediately familiar with her name, but it’s only once in a while we actually meet another [name_f]Jillian[/name_f]. I also think it just sounds so bright and cheerful and happy, which is exactly what she is. I [name_u]LOVE[/name_u] your combo of [name_f]Jillian[/name_f] [name_f]Kate[/name_f], [name_f]Kate[/name_f] has always been a favorite of mine, but [name_f]Jillian[/name_f] Maybry is very sweet as well.
That is really sweet. Made me smile. 
[name_f]Mabry[/name_f] is perfect for a girl as it is; no need for a “girl version” of Maybree. A girl can have a strong name like [name_f]Mabry[/name_f].