Yeah, when it gets this deep into the language weirdness, better to just leave it in.
Page 6-9, the reason she's posing like that with the pyon is that pyon is stereotypically a bunny sfx for their jumping. You really can use it for anyone jumping (Ogami Tsumiki uses it a lot for a werewolf girl jumping), but mostly 'pyon' is understood to be bunny hop so she's making the bunny ears.
Thanks for these, they're cute!