Mood moo moooo
I don’t think [name]Caitlin[/name], [name]Carys[/name], and [name]Seren[/name] are too matchy. I [name]LOVE[/name] the name [name]Carys[/name], but I might be partial since we have a niece named [name]Karis[/name] (I think it’s pronounced the same anyway…) Question just out of curiosity: On the name [name]Seren[/name], is the emphasis on the first or last syllable? I thought it would be on the first, but just checking. It’s very pretty. Some of my favorite combos using your list:
[name]Carys[/name] [name]Finley[/name] (I know you said you only like it with [name]Tessa[/name], but I think it sounds nice with [name]Carys[/name] too)
[name]Seren[/name] [name]Pearl[/name] (love the middle name [name]Pearl[/name]. It was 1 of 2 we were considering for our daughter)
[name]Seren[/name] [name]Penelope[/name]
[name]Seren[/name] [name]Elise[/name]
[name]Cecily[/name] [name]Pearl[/name]
Out of your boy choices, I like [name]Everett[/name] [name]Reid[/name] the best. With the middle name [name]Noam[/name], I’d probably see “gnome” at first like you said, but that’s just because I wasn’t familiar with the name. Looked it up on another site that has pronunciations (babynamesworld.com) and it confirms your way of pronouncing it. Since you picked it as a middle name, it’s not like all the kids at school would know him as that anyway so I say go for it if you love it.
Whoops, my mistake thinking [name]Karis[/name] was pronounced the same as [name]Carys[/name]. I had to look it up after that other [name]Carys[/name] thread and the other site with the pronunciations says KAH riss. Still a beautiful name 
[name]Seren[/name] is Seh ren
I’ve worked out my favorites. They are in order. Let me know what you think.
[name]Carys[/name] [name]Rowan[/name]
[name]Carys[/name] [name]Finley[/name]
[name]Carys[/name] [name]Francesca[/name]
[name]Carys[/name] [name]Vera[/name]
[name]Carys[/name] [name]Arden[/name]
[name]Carys[/name] [name]Emeline[/name]
[name]Seren[/name] [name]Tessa[/name]
[name]Seren[/name] [name]Elise[/name]
[name]Seren[/name] [name]Freya[/name]
[name]Seren[/name] [name]Athena[/name]
[name]Seren[/name] [name]Ivory[/name]
[name]Seren[/name] [name]Penelope[/name]
[name]Carys[/name]
Names I like only as MNs:
[name]Athena[/name]
[name]Francesca[/name] (too long?)
[name]Lark/name
[name]Vera[/name]
No I don’t think they’re too matchy! In fact, [name]Carys[/name] and [name]Seren[/name] are both Welsh, and [name]Caitlin[/name] was the wife of the famous Welsh author [name]Dylan[/name] [name]Thomas[/name] so is also a very popular name in [name]Wales[/name] although it’s Irish. This was the reason we chose it for my little sister!
Of your combos I like:
[name]Carys[/name] [name]Rowan[/name] (have you considered [name]Carys[/name] [name]Rowena[/name]? I think the flows a little better)
[name]Carys[/name] [name]Finley[/name]
[name]Carys[/name] [name]Francesca[/name]
[name]Seren[/name] [name]Elise[/name]
[name]Seren[/name] [name]Penelope[/name]
I like:
[name]Caitlin[/name] [name]Harper[/name], [name]Carys[/name] [name]Rowena[/name] and [name]Seren[/name] [name]Elise[/name] 
Thanks! While I love [name]Rowan[/name], [name]Rowena[/name] is a bit of a turn off for me…makes me think of an old lady >.<.
I love [name]Seren[/name] [name]Elise[/name]. Her initials would be “SEW” which I just recently took up so thats cute but the other girls wouldn’t have a word…not sure that bothers me but I’m just trying to keep in mind all rivalry issues. [name]Elise[/name] and [name]Tessa[/name] are both equally cute and feminine [name]IMO[/name]. They were really close in popularity last year (208 and 211)…hmm, hard to choose between those two!!