why is the cast of the Scions so...elvish now.

[Iscah]

I find it really weird that in SHB alphy, alisaie, y'shtola and urianger just abandon whatever they are doing to follow you,

What they're doing is filling in time until you arrive so they can help you with the Exarch's grand plan to save everything.

Estinien and Tia

Picking on you but this is a generalised rant – I don't know why so many people go for "Tia" as the bit of the name to call him by when everyone within the game calls him "G'raha" or (in Krile's case) "Raha".

Tia isn't even a unique name to him, but a tribe rank shared by most male Seeker Miqo'te, so it's not something that really works as an identifier. It's like calling him "Mister".