What do you think of twins names [name_f]Kathleen[/name_f] ([name_f]Kate[/name_f]) and [name_f]Ann[/name_f]? Should I spell [name_f]Ann[/name_f] with or without an E? [name_f]Ann[/name_f] has family connections but [name_f]Anne[/name_f] would work just as well, and I have read comments that say it is more complete with that extra E. The other option would be [name_f]Kathleen[/name_f] ([name_f]Kate[/name_f]) and [name_f]Jane[/name_f], is that better? If both name end in an N sound are they too matchy?
I personally like the [name_f]Anne[/name_f] spelling better, but it’s up to you. Is the family meaning behind the [name_f]Ann[/name_f] spelling drawing you to it? Or does it not matter so much?
[name_f]Jane[/name_f] is another good option. I think either it or [name_f]Anne[/name_f] would go nicely with [name_f]Kathleen[/name_f]. It’s not too matchy to share ending sounds, because the names are otherwise not matchy-matchy.
[name_f]Kathleen[/name_f] and [name_f]Anne[/name_f] are lovely and timeless together! I personally prefer the -e spelling, it does look more complete to me. I think [name_f]Kate[/name_f] and [name_f]Annie[/name_f] would be very sweet together as well. I also like [name_f]Kathleen[/name_f] and [name_f]Jane[/name_f], but imo they do sound a little matchy together, more so than Kathleen and Anne.
All three names end in the -n sound, so if you want the names to have different endings another name needs to be chosen to go w/[name_f]Kathleen[/name_f].
I prefer [name_f]Anne[/name_f] w/[name_f]Kathleen[/name_f], & prefer [name_f]Anne[/name_f] with the -e at the end. I’m always reminded of [name_f]Anne[/name_f] of [name_u]Green[/name_u] Gables & her strong preference for [name_f]Anne[/name_f] w/an e! 
[name_f]Anne[/name_f] is my favorite as a sister name for [name_f]Kathleen[/name_f], but I really don’t think you can go wrong with any of your options.
I prefer [name_f]Jane[/name_f] over [name_f]Anne[/name_f], but think, that preference aside, both go equally well with twin [name_f]Kathleen[/name_f]. I love [name_f]Kate[/name_f], and love [name_f]Annie[/name_f] with it for [name_f]Anne[/name_f]'s nn, or [name_f]Janey[/name_f] or [name_f]Jane[/name_f]. I generally prefer [name_f]Anne[/name_f] with an e, but it’s not a big deal.
Personally I would modernise [name_f]Anne[/name_f] to [name_f]Anna[/name_f] or [name_f]Anya[/name_f], but that’s just my preference.
I prefer [name_f]Jane[/name_f], though if she’s going to be [name_f]Ann/name_f I like the [name_f]Anne[/name_f] spelling more, it looks more complete
I also like the pp’s suggestions of changing [name_f]Anne[/name_f] to [name_f]Anna[/name_f]/[name_f]Anya[/name_f], if you’d consider it! They’d still be honor names but feel much fresher
Both are great options.
I understand what people mean when they say [name_f]Anne[/name_f] seems a more “complete” or sophisticated spelling, but I also think the simplicity of [name_f]Ann[/name_f] is very appealing.
If [name_f]Anne[/name_f] is the more common spelling where you live (as it is in the USA), though, you might find her name gets misspelt if you go with [name_f]Ann[/name_f].
If you go with [name_f]Jane[/name_f], would you be likely to use [name_f]Ann[/name_f]/[name_f]Anne[/name_f] as [name_f]Kathleen[/name_f]'s middle name? I think the family spelling works well as a middle: [name_f]Kathleen[/name_f] [name_f]Ann[/name_f].
Good luck with the decision, and congratulations!
I like the idea of [name_f]Kathleen[/name_f] (nn [name_f]Kate[/name_f]) and [name_f]Anna[/name_f] (nn [name_f]Annie[/name_f]) together, or otherwise any two of [name_f]Kate[/name_f], [name_f]Anne[/name_f] and [name_f]Jane[/name_f]. They seem more balanced to me.
If not, [name_f]Jane[/name_f] goes marginally better with [name_f]Kathleen[/name_f] to me but I really appreciate the elegakce of [name_f]Anne[/name_f].