[name_m]Hi[/name_m] there.
[name_f]Maeve[/name_f] [name_f]Eleanor[/name_f] is gorgeous! I live in an urban U.S. city as well, & a few of my little nephews have hard to spell & say Irish names. People have to be corrected on them reasonably often, but I still feel like it’s worth it to have a beautiful authentic Gaelic name.
Here are my thoughts on your list-
[name_f]Saoirse[/name_f] Quinn-This will definitely confuse people more than [name_f]Maeve[/name_f], but I think it’s nice as a little sister. It’s one of those names that’s an equal balance of pretty & fancy but still feels sort of badas*.
[name_f]Aine[/name_f] Sloane-I love love [name_f]Aine[/name_f]! It’s one of my favorites. I’ve always been hesitant to put it on my actual usable list because it’s hard to say right without an Irish accent. I don’t worry about people saying or spelling it wrong, but I worry about me saying it wrong. Maybe you’re better at it! Have you thought of [name_u]Sloane[/name_u] as a fn? That seems perfect with [name_f]Maeve[/name_f]. It’s Gaelic & somewhat gender neutral, but leans feminine. It’s a bit more well known, so maybe won’t confuse people too much.
[name_f]Roisin[/name_f] Caoimhe-This is a cool combo. [name_f]Roisin[/name_f] is definitely tricky to say & spell for Americans, I would think. And it’s honestly not my favorite. I think something about it sounds heavy. What about just [name_f]Rose[/name_f] as a full name? [name_f]Rose[/name_f] [name_f]Caoimhe[/name_f] is stunning with [name_f]Maeve[/name_f] [name_f]Eleanor[/name_f].
[name_f]Elliotte[/name_f] Saoirse-I like the idea of [name_f]Etta[/name_f] or El(maybe prefer Elle) with [name_f]Maeve[/name_f]. But [name_f]Elliotte[/name_f] looks off. And also, it’s pretty boyish to me (spelled Elliott.)
[name_f]Norah[/name_f] Morrigan-This is an interesting combo. It’s a bit ‘r’ & ‘n’ heavy, but maybe I’m just being picky. I love [name_f]Norah[/name_f], but think that [name_f]Nora[/name_f] looks even sleeker. It’s pretty popular in my neck of the woods, at least. Still really a nice name & great w/Maeve.
A few more ideas-
[name_f]Alice[/name_f]
[name_f]Bridget[/name_f]
[name_u]Clare[/name_u]
[name_f]Catriona[/name_f] nn [name_f]Cate[/name_f]
[name_f]Colleen[/name_f]
[name_f]Celeste[/name_f]
[name_f]Ciara[/name_f]
Etta-just [name_f]Etta[/name_f]?
[name_f]Eloise[/name_f]
[name_u]Fern[/name_u]
[name_f]Fiona[/name_f] 
Gwen(dolen) or [name_f]Gwyneth[/name_f]?
[name_f]Maren[/name_f]
[name_f]Nuala[/name_f]!
Niamh-maybe too close to [name_f]Maeve[/name_f]
[name_f]Pearl[/name_f]
[name_u]Skye[/name_u]
[name_f]Stella[/name_f]
Tess(a)
[name_u]Wynn[/name_u]
[name_f]Hope[/name_f] this helps. 
. Have you considered Anya rather than Áine? Technically they have different roots but they would sound the same in an American accent.