So you have to name two siblings, with a subtle matching theme, such as;
[name]Oscar[/name] and [name]Scarlett[/name] (s-c-a-r)
[name]Alicia[/name] and [name]Alexander[/name] ([name]Alice[/name] and [name]Alex[/name])
[name]Jasper[/name] and [name]Reuben[/name] nn [name]Ruby[/name] (Gemstones)
or even something like [name]Oscar[/name] [name]REDford[/name] and [name]SCARLETT[/name] [name]Olivia[/name]!
Have fun!
[name]Anthony[/name] & Theanna
[name]Robert[/name] [name]Bob[/name], [name]Janet[/name] [name]Jan[/name], [name]Margaret[/name] [name]Meg[/name] (two syllable names ending with “t” with three-letter, one syllable nicknames)
[name]Oliver[/name] & [name]Violet[/name] (both share all the same letters, except one)
[name]Imogen[/name] and [name]Cedric[/name] - both names that arose from a mispelling in classic literature ([name]Cymbeline[/name] and [name]Ivanhoe[/name])
[name]Ethan[/name] and [name]Audrey[/name]. … [name]Both[/name] mean strong.
Wel, I have a personal one. My daughter is [name]Alice[/name] and I [name]LOVE[/name] the name [name]Celia[/name] at the moment. Same letters different name 
[name]Fuchsia[/name] & [name]Carmine[/name]
… Colors close to pink!!
[name]Melody[/name], [name]Aria[/name], [name]Viola[/name] (musical names)
[name]Celeste[/name], [name]Aurora[/name] and [name]Luna[/name] (meaning sky, dawn and moon)
[name]Ari[/name] & [name]Ira[/name] (Reverse them and they’re the other name)
[name]Noel[/name] & [name]Leon[/name] (same thing)
[name]Ava[/name] & [name]Elle[/name] (spell them backwards and they’re the same)
[name]Lana[/name] & [name]Naomi[/name] (spell them backwards and they’re both not very nice lol)
[name]Blaise[/name] & [name]Isabel[/name] (anagrams of eachother)
[name]Cornelia[/name] & [name]Caroline[/name] (also anagrams)
[name]Diana[/name], [name]Aidan[/name] and [name]Nadia[/name] (anagrams as well)
i have a bailey and liberty they both have same letters apart from a r & t
[name]Rosemary[/name] and Remembrance ([name]Rosemary[/name] is a symbol of remembrance)
[name_f]Decima[/name_f] & [name_m]Dex[/name_m] (both mean ten)
[name_u]Mars[/name_u] and [name_f]Maia[/name_f] (the [name_m]Roman[/name_m] god [name_u]March[/name_u] is named after, and the Greek goddess [name_f]May[/name_f] is named after)
[name_f]Clemency[/name_f] and [name_f]Geneva[/name_f] (after the [name_f]Geneva[/name_f] Convention) I think could also be really cute
[name_f]Anita[/name_f] & [name_f]Tiana[/name_f] (anagrams)
[name_f]Esme[/name_f] & [name_f]Willow[/name_f] (both began and end with the same letter)
[name_f]Aretha[/name_f] & [name_m]Benjamin[/name_m] (LN [name_m]Franklin[/name_m])
[name_f]Beatrix[/name_f] and [name_m]Xavier[/name_m] (one ends with X, one starts with X)