OP,
You've chosen some nice name options there.
Niamh: one of my very favourites; beautiful name, and no doesn't matter if you've no Irish heritage.
(And to pre-empt the usual warnings of doom, don't be concerned about the spelling issue: names as familiar as Catherine/ Katherine/ Katharine etc. can cause just as many complications, frankly! Pronunciation-wise, people can blooming well just learn fast 
Keep the original Irish names alive, I say).
Niamh, with Stella as middle name, would be rather special, btw: "radiant and bright star".
Eden, Emmeline, Aurora: all lovely.
(prefer the Emme-LEEN pronunciation to Emme-LINE, but perhaps you disagree?).
Cora: afraid will always be connected in my mind with Cora-Beth, from
The Waltons
(shopkeeper Ike's interfering, gossipy wife).
No strong opinions either way on the rest.
Of your boys' names:
I do love Louis (if pronounced LOO-ee, rather than LOO-iss).
Stanley's becoming quite popular around these parts, same Edwardian vintage bracket as Bertie/ Wilfred/ Archie. (Percy would fit in there, too, I suppose?). Do you like Stan as much, though? Because I'd guess he'd likely become that half the time.
Grayson: I automatically thought Grayson Perry, the artist. Have never heard it otherwise.
Max/ Liam: very, very popular here.
Rufus is great. Love Rory/ Ruairi/ Ruaidhri as well.
(Bonus points if used for a baby redhead) 