We have an [name_u]Evelyn[/name_u]. We call her [name_f]Evie[/name_f] sometimes (eh-vee) but usually [name_u]Evelyn[/name_u]. For her sister, we are considering [name_f]Eleanor[/name_f], [name_f]Molly[/name_f] or [name_f]Madeline[/name_f]. [name_f]Do[/name_f] [name_u]Evelyn[/name_u] and [name_f]Madeline[/name_f] sound too matchy? Is it strange that they rhyme but are spelled differently? Is [name_f]Eleanor[/name_f] too close to [name_u]Evelyn[/name_u]? [name_f]Molly[/name_f] is definitely my 3rd choice of the 3. Thanks for your feedback!
Well I automatically read [name_f]Madeline[/name_f] as mad-el-line rather then -lyn. Perhaps you could pronounce it that way? I like the [name_f]Madeleine[/name_f] spelling more 
[name_f]Eleanor[/name_f] really compliments [name_u]Evelyn[/name_u] quite nicely without being matchy. [name_f]Evie[/name_f] and [name_f]Ellie[/name_f] would be adorable as well and [name_f]Eleanor[/name_f] [name_f]Madeleine[/name_f] is a really sweet combo.
I read [name_f]Madeline[/name_f] as -lynn and [name_f]Madeleine[/name_f] as -line, so I think [name_f]Madeline[/name_f] sounds too similar.
I know an [name_u]Evelyn[/name_u] pronounced ee-ve-lyn, so I would think [name_f]Eleanor[/name_f] goes quite nicely, however if you pronounce it eh-ve-lyn then despite the match being different I still think it is the best of the three. It is on the same level of loveliness!
Well, I’d have to go with [name_f]Molly[/name_f]. I’m not a fan of [name_f]Madeline[/name_f] (with either pronunciation) to begin with and I don’t like the way [name_f]Madeline[/name_f] prn with a lynn sound rhymes with [name_u]Evelyn[/name_u] at all. As a personal preference, I don’t like siblings to share a first initial, so [name_f]Molly[/name_f] gmv!
A few suggestions that popped into my head
[name_u]Evelyn[/name_u] and…
[name_f]Adele[/name_f]
[name_f]Corinne[/name_f]
[name_f]Camille[/name_f]
[name_f]Helena[/name_f]
[name_f]Bridget[/name_f]
[name_f]Celia[/name_f]
[name_f]Rosalie[/name_f]
[name_f]Stella[/name_f]
Good luck!
[name_f]Molly[/name_f] goes with [name_u]Evelyn[/name_u] the best out of your chosen names. Here are some other choices…
[name_u]Evelyn[/name_u] and [name_f]Sara[/name_f]
[name_u]Evelyn[/name_u] and [name_f]Grace[/name_f]
[name_u]Evelyn[/name_u] and [name_u]Morgan[/name_u]
[name_u]Evelyn[/name_u] and [name_f]Meghan[/name_f]
[name_u]Evelyn[/name_u] and [name_f]Annabelle[/name_f]
[name_u]Evelyn[/name_u] and [name_f]Marielle[/name_f]
[name_u]Evelyn[/name_u] and [name_u]Ashley[/name_u]
[name_u]Evelyn[/name_u] and [name_u]Taylor[/name_u]
[name_u]Evelyn[/name_u] and [name_u]Spencer[/name_u]
Both [name_u]Evelyn[/name_u] and [name_f]Madeline[/name_f] are in my top 5 favorites and I think they go super well together. Although, I prefer the Mad-uh-[name_f]LINE[/name_f] pronunciation over -lyn. I think [name_f]Madeline[/name_f] (-line) ages better as well. [name_f]Eleanor[/name_f] is a little too matchy with [name_u]Evelyn[/name_u] and [name_f]Molly[/name_f] is too cutesy in my opinion.
I think that [name_f]Eleanor[/name_f] is too matchy and [name_f]Madeline[/name_f] is too if you pronounce it mad-eh-lin. If it’s [name_f]Madeleine[/name_f] (mad-eh-line), I think it definitely works!
What about [name_f]Melinda[/name_f]? [name_f]Miranda[/name_f]? [name_u]Evelyn[/name_u] and [name_f]Miranda[/name_f] would be absolutely amazing.
I love your choices, but [name_f]Eleanor[/name_f] and [name_f]Madeline[/name_f] are both too close to [name_u]Evelyn[/name_u]. [name_m]How[/name_m] about:
[name_f]Cora[/name_f]
[name_f]Cecelia[/name_f]
[name_f]Alice[/name_f]
[name_f]Amelia[/name_f]
[name_f]Beatrice[/name_f]
[name_f]Vivienne[/name_f]
[name_f]Sylvie[/name_f]
[name_f]Corinna[/name_f]
[name_u]Ruby[/name_u]
[name_f]Lucy[/name_f]
I think if you’re planning to have more than 2 kids, both [name_f]Eleanor[/name_f] and [name_f]Madeline[/name_f] are too matchy with [name_u]Evelyn[/name_u]. If you’re planning to have just 2, I think it’s easier to use such similar sounding names.
Some names I think coordinate well with [name_u]Evelyn[/name_u]:
[name_f]Charlotte[/name_f]
[name_f]Ann[/name_f]/[name_f]Annabelle[/name_f]
[name_f]Rose[/name_f]/[name_f]Rosalie[/name_f]/[name_f]Rosemarie[/name_f]
[name_f]Elizabeth[/name_f]
[name_f]Kathryn[/name_f]/[name_f]Cathryn[/name_f]
[name_f]Margaret[/name_f]/[name_f]Margery[/name_f]
[name_f]Sarah[/name_f]