Henrietta will know Holden as her ~competition~ so although he's quiet she won't underestimate him on the pitch. I like the idea of him having an awkward crush! I mean if you want they could've dated last year, and maybe Etta was just way too outgoing for Holden so they broke up after a couple of months? I don't mind! Up to you. :)
Ahhh Sylla sounds like so much fun, although Henrietta probably thinks her hobbies are a bit weird, haha. But she appreciates being thought of as badass, and Etta talks to pretty much everyone so they'll interact at some point. :)