[name]Levi[/name] - not my personal favorite, but I think it goes really well with your daughter’s names. Would you like to be able to use a nn? Your daughter’s names are fairly long and easily yield nicknames, but most of your boys’ names don’t quite do that. I don’t think it’s a problem–my girls’ list and boys’ list is the same–but I was just curious. 
[name]Preston[/name] - not really my style at all but I think it could work. Honestly, though, this is my least favorite as I think it’s more trendy/doesn’t age as well as your other options.
[name]Everett[/name] - love! This (besides maybe [name]Asher[/name]) is my favorite name in general from this list, and [name]Everett[/name] is too cute with your girls’ names.
[name]Luke[/name] - I like it and I think it’s a lovely name, but next to your long, flowy daughter’s names, I think you need something a bit longer. What about [name]Lucian[/name]/[name]Lucien[/name], [name]Luca[/name], or even [name]Lucas[/name]?
[name]Ethan[/name] - I love it, but compared to your girls, it’s a bit popular. Does that bother you? All of these are really great and I can see them all as a little brother to your girls’ names, so I’m just trying to come up with something that’ll help make the decision easier, haha.
[name]Asher[/name] - my second favorite name in general–I lovelovelove [name]Asher[/name] nn [name]Ash[/name]. I think it’s so dashing and handsome, although I’m not sure [name]Asher[/name] goes as well with G_abriella and C_ambria as the other choices do.
[name]Logan[/name] - this is probably my second-to-least favorite. I think it goes well with your girls, but it feels rather dated/trendy/overdone to me.
[name]Eli[/name] - cute and handsome, but I think something like [name]Elliot[/name], [name]Elias[/name], or [name]Elijah[/name], nn [name]Eli[/name], would work better with your girls.
[name]Noah[/name] - awww. I love [name]Noah[/name] so much. I think some of these fit better with G_abriella and C_ambria, but I can’t help but love it. It is a bit popular compared to your girls’ names, too, like [name]Ethan[/name].
[name]Jacob[/name] - I love [name]Jacob[/name], but couldn’t use it anymore, due to its popularity. I know dozens of Jacobs, haha. I think he’s a lovely mn, though. Stylistically, I think [name]Jacob[/name] is a great match with G_abriella and C_ambria, though!
[name]Isaac[/name] - this is lovely! It’s not usually a favorite of mine but I think he’s lovely, refined, charming, quirky, and handsome all on his own and perfectly matches your other daughters. This would be my second pick, I think.
Good luck!