I'd say all those pairings you listed are the best, except maybe Ayra-Lex. I've played FE4 three times, pairing Ayra with Lex, Noish, and Holyn. All three have their quirks, Lex giving the kids paragon, Noish giving them good skills, and Holyn giving them major Od blood. The worst of these is Holyn in my opinion, because even though having them able to use Balmung sounds cool, they already have great skill and speed stats, and Shannan needs the sword more than them. Then between Noish and Lex I'd say it's a tie. Gaining double EXP is enough to match the power of critical and accost, so it's really up to you on this. I think Lex is easier to pair with Ayra compared to Noish, though, and Noish goes really well with Briggid as well.