I used the word mutter just because Gabino is speaking in a low voice (he's standing right over Eskiera, and is rather tired himself). I could've used 'whisper' but that would imply he's hiding something, which is not the case. The word 'sigh' would've worked, but I already used it in another part of the text.
The humans know the elf as 'Shrike', although they suspect it's a fake name. Shrike may or may not conform to (human) gender norms, but mostly it's just another aspect of their identity the humans are not aware of. So they refer to Shrike with singular they pronouns for lack of another option.
I'll look into the paragraphs! This is my forst time writing in this format.