I’ve always really loved the names [name_f]Maggie[/name_f], [name_f]Molly[/name_f], and [name_f]Annie[/name_f], but I dismissed them originally with our first daughter because I didn’t think people would like them with our last name Muncy. I don’t mind alliteration or repeated sounds in a name and I am trying less to worry about how people we know may judge our name choices for our second child, so I’m putting them back on the table. That being said, I’m getting a little caught up on how close they sound to our daughter’s name. Are [name_f]Maggie[/name_f], [name_f]Molly[/name_f], and [name_f]Annie[/name_f] too close to older sister [name_u]Adley[/name_u]? All three names share rhythm and at least one sound with [name_u]Adley[/name_u], so I’m afraid they don’t work well together.
Maggie and [name_u]Adley[/name_u] have the same A sound for me so I’d say they’re too close.
Molly and [name_u]Adley[/name_u] are not at all too close. I wouldn’t personally use [name_f]Annie[/name_f] just because I like the idea of siblings with different initials but it’s also not too close to [name_u]Adley[/name_u].
Adley and [name_f]Annie[/name_f] are too close, but the other 2 are good - with [name_f]Molly[/name_f] being the better option imo.
Maggie is the least similar, and I like it a lot with [name_u]Adley[/name_u]! [name_f]Molly[/name_f] is a little similar but not too close. [name_f]Annie[/name_f] is the one that seems a little too match-y, imho. 
Love [name_f]Maggie[/name_f] I think it goes great with [name_u]Adley[/name_u]! [name_f]Molly[/name_f] is a little too similar to [name_u]Adley[/name_u] imo just because of the -ley ending. Same goes for [name_f]Annie[/name_f], both names are really sweet but they are a lot alike.
The only one I think is too similar is [name_f]Annie[/name_f]! I think [name_f]Maggie[/name_f] & [name_f]Molly[/name_f] share some sounds, but aren’t too close to [name_u]Adley[/name_u]. I especially like [name_u]Adley[/name_u] & [name_f]Maggie[/name_f]! (Also Magg!e Muncy is such a great name!)
Maggie and [name_f]Annie[/name_f] are too close, but [name_f]Molly[/name_f] and [name_u]Adley[/name_u] are just fine!
I really like them all with [name_u]Adley[/name_u] especially [name_f]Annie[/name_f] and [name_u]Adley[/name_u] as it’s a very sisterly cuteness with the slight name similarities! [name_f]Molly[/name_f] Muncy sounds a bit plain and boring though on a whole, but definitely [name_f]Maggie[/name_f] and [name_f]Annie[/name_f]!
[name_u]Ever[/name_u] thought of:
[name_f]Hallie[/name_f]
[name_f]Margo[/name_f] (favourite with your last name)
[name_f]Eva[/name_f]
[name_f]Avis[/name_f]
Keefa
[name_f]Charlotte[/name_f]
[name_f]Florencia[/name_f]
[name_f]Paulina[/name_f]
[name_f]Valencia[/name_f]
[name_f]Zadie[/name_f]
Annie feels a tad close but not unusably so
I think they’re okay together!
Adley and [name_f]Maggie[/name_f] is a bit of a mouthful
Adley and [name_f]Annie[/name_f] is lovely
Adley and [name_f]Molly[/name_f] works
This
Exactly what I was thinking!
Molly is your best bet! It’s not so similar at all.
Thank you all for the responses! There definitely isn’t any sort of consensus on whether the names are too close or not. lol But that’s ok and not entirely unexpected. I actually find it quite interesting to see what makes people feel a name is too close or fine to use. The majority does seem to find Annie too close and that’s the one I have the hardest time with, too. It is my favorite as there are family connections, but using it isn’t a necessity.
@greentiger I have considered some of those names, but not all. [name_f]Margo[/name_f]/Margot was on my list quite a while ago, actually. I love [name_f]Hallie[/name_f], [name_f]Charlotte[/name_f], and [name_f]Eva[/name_f]. The others I’d have to think a bit more on as I’ve never considered them! Thanks for the suggestions!
You could always use [name_u]Anne[/name_u] as a mn with [name_f]Maggie[/name_f] or [name_f]Molly[/name_f], which would still honor those family connections. 
[name_f]Molly[/name_f] and [name_u]Adley[/name_u] work well together! The other two are too close for me.
I probably should have thought of that given [name_u]Anne[/name_u] is my middle name, but I did not. lol
To answer your question, all of these names sound pretty similar to me. I don’t have a sister myself, but from what I understand, they like to stand out from each other. I would suggest using one of these as a middle name perhaps, but looking for a more different first name.
To address your previous concerns about alliteration - I think you got it right with [name_u]Adley[/name_u], where only one sound is repeated (the ee sound at the end). I think names like [name_f]Maggie[/name_f] and [name_f]Molly[/name_f] would be overdoing it because they start and end with the same sounds as the last name, taking them from just alliteration to sing-song.
So I think what might be perfect for you is an M name that does not end in an ee sound. Something like [name_f]Marina[/name_f] or [name_f]Margot[/name_f], perhaps. I hope this is helpful
I appreciate the detailed feedback. =] Putting [name_f]Maggie[/name_f] or [name_f]Molly[/name_f] in the middle spot, for me, sounds even worse than using them as a first name. I know you don’t hear first, middle, and last names together very often, but if you did, I feel like [name_f]Katherine[/name_f] [name_f]Maggie[/name_f] [name_m]Mitchell[/name_m] or [name_u]Arden[/name_u] [name_f]Molly[/name_f] [name_m]Smith[/name_m] sound like the names are in the wrong order. [name_f]Maggie[/name_f] and [name_f]Molly[/name_f] do not strike me as middle names, but that’s just me.
I see your point about alliteration vs sing-song, although [name_u]Adley[/name_u] Muncy has no alliteration. It just has shared sounds. [name_f]Maggie[/name_f] and [name_f]Molly[/name_f] have alliteration and shared sounds, so they do move into the realm of sing-song. I don’t always mind that, though. [name_m]Just[/name_m] depends on the names for me.
I have considered [name_f]Margot[/name_f] in the past and for a short period of time she was a real consideration, but I just don’t love her. I am not after an M- name specifically. I just happen to really like [name_f]Maggie[/name_f] and [name_f]Molly[/name_f]. I don’t like very many others except, perhaps, [name_u]Mackenzie[/name_u]. And I prefer that on a boy.