Thought I would expand on my previous comment.
Lasairfhíona - [name_f]Love[/name_f] this! 
Hadn’t heard of it before but love it! Although it’s long, it sounds so pretty! Plus flame of wine sounds so cool!! 
It’s now my new favorite [name_m]Irish[/name_m] girl name 
[name_f]Muireann[/name_f] - I like meanings related to the sea and the mermaid story is cool 
[name_f]Alannah[/name_f] - probably the easiest internationally out of your girls list but I like some of these other ones better
[name_f]Fia[/name_f] / [name_f]Fiadh[/name_f] - simple and pretty, I can see why it’s so popular in [name_f]Ireland[/name_f] right now. I think I prefer it spelled [name_f]Fiadh[/name_f] to look more complete but [name_f]Fia[/name_f] would make it easier internationally. Both spellings are lovely!
[name_f]Eithne[/name_f] - You’re pronunciation does make more sense but I’m personally not usually into ‘th’ sounds (the d th mix is fine tho) so this updated pronunciation isn’t doing it for me. Plus the nut kernal meaning is a bit odd but perhaps it’s because I don’t understand the poetry reference. Could still work for you and others if you love it though
Siún - makes me think of trying to shoo someone away. It can be nice if you like the meaning though
Clíodhna - it’s pretty and I love the idea of being [name_f]Queen[/name_f] of the Banshees! 
Aibhilín - love it! Already loved [name_f]Evalyn[/name_f] and [name_f]Aveline[/name_f] so this goes right along with them! I heard in a video however that there’s a few pronunciation options if you’re concerned about that at all. Also, idk about [name_f]Ireland[/name_f] but [name_f]Evelyn[/name_f] has been in the top 20 for the past 10 years in the US
[name_f]Naoise[/name_f] - I’m not big on sh sounds but otherwise there isn’t really anything wrong with it if you don’t mind the legend behind it
[name_f]Onóra[/name_f] - pretty and honorable
[name_f]Sadhbh[/name_f] / [name_f]Sadbh[/name_f] - I think it’s cool that there’s a few princesses with this name. The legend about the deer is also interesting 
Tuathla - I like the meaning! 
Fírinne - sounds nice! I can see how the first syllable might sound like fear to people but I like it!
Líadan - sounds sweet
[name_f]Saorla[/name_f] - love it! And the meaning too
Méadbh - Ik a lot of berries like [name_f]Maeve[/name_f] but I’ve just never been a fan
[name_f]Cadhla[/name_f] - [name_f]Beautiful[/name_f]
Síoda - it’s alright
Éadaoin - yeah, jealousy isn’t the best but I’ve seen people interpret it as passionate, fiery spirit, or full of charisma to put a better modern spin on the meaning
[name_m]Daithí[/name_m] - it’s ok but the meaning is cute, makes me think of a deer
[name_m]Iarla[/name_m] - [name_f]Love[/name_f] it and the meaning! I like the gentle sounds for a boy, probably my new favorite
[name_m]Tadhg[/name_m] - it’s alright
Donncha / Donnchadh - I like it!
Murchadh - I just realized after you spelled it out that it looks like someone is saying 'Murica as a shortened and often sarcastic form of [name_f]America[/name_f]. Not sure if that bothers you but otherwise I like the sound and meaning 
Faolán - my favorite 
[name_m]Tomás[/name_m] - the pronunciation I was looking at seemed to indicate that the first syllable was tuh or tuw so I was going to put the same description as [name_m]Liam[/name_m]. But with ‘th,’ then my thoughts are like [name_f]Eithne[/name_f] in that there’s nothing wrong with it, it’s just not to my personal taste
[name_m]Liam[/name_m] - it’s alright but pretty basic and simple compared to your other names. It also don’t really scream [name_m]Irish[/name_m] if you want people to immediately know that just by looking at the name but are easier for foreigners so just depends what you’re going for
Maidhc & [name_f]Eileanóra[/name_f] - they’re alright. If you want names that are familiar to [name_f]English[/name_f] speakers when they hear and say it but obviously [name_m]Irish[/name_m] after seeing it written, then these 2 are good
Gearóid - it’s fine but not a fan
Dónal - I like it!
[name_m]Fiachra[/name_m] - haven’t heard of this but I like it!
[name_m]Luan[/name_m] - sounds cute and sweet
[name_m]Art[/name_m] - cute but would prefer it as a nickname
[name_m]Lorcan[/name_m] - love it!
Sibset ideas:
[name_f]Fiadh[/name_f], Éadaoin, & [name_m]Lorcan[/name_m] meaning wild, fiery, and fierce!
[name_m]Fiachra[/name_m], Faolán, & [name_f]Sadhbh[/name_f] - [name_f]Raven[/name_f], little wolf, and deer can also add bear with a name like Bearnáirdín
[name_m]Daithí[/name_m] & [name_f]Sadhbh[/name_f] - swift and nimble like a deer
[name_f]Muireann[/name_f], Aibhilín, & Murchadh
Lasairfhíona & Clíodhna
Dónal, [name_m]Iarla[/name_m] (or Saorla), [name_f]Cadhla[/name_f], & [name_m]Luan[/name_m]
Síoda & Líadan
Fírinne & [name_f]Onóra[/name_f] - [name_m]Truth[/name_m] & [name_f]Honor[/name_f]
[name_f]Eileanóra[/name_f] & Méadbh
Donnchadh/Donncha & Murchadh Does it rhyme too much?
I’d probably avoid [name_m]Iarla[/name_m] and [name_f]Saorla[/name_f] together. As much as I really love both of them, they sound too similar together 
same with [name_f]Fiadh[/name_f] and [name_m]Fiachra[/name_m] 
so I still like to look them up to be sure. But once you think you got some of the rules down, I found this video to test myself. She also mentions some of the names on OP’s list like Lasairfhíona, Aibhilín, and Éadaoin
) means ‘grey lady’ , poetess in [name_m]Irish[/name_m] mythology
)
So cool to see which ones stand out to you!
Sorry about the pronunciation 
I’ve tried to explain them in a reply further up, hopefully it makes sense. [name_m]Loving[/name_m] your selection!
