IIRC at this point the Guide has taken enough damage to lose the ability to hop dimensions. Thus it is stuck here taking more damage from Liam so the only choice is to just attempt to off him.
I still remember an article about a ps5 scalper who boldly claimed they were "performing a service for the people."
Yeah no buddy you are the problem, not the solution.
The grass thing might have a couple other meanings: in Demon's Souls you eat grass to heal thus meaning 'you can heal here'. And also that Grass=a substitute for laughing in a meme-y way, so having a giggle at the enemies dying to balls.
So Amane had another reason to block this fool, since this isn't their first weird dm from them. Back in Chapter 101, Page 11 he dmed Amane about becoming a gravure idol. So already proved himself a weirdo, then this new dm was nope.
It's a visual choice from the original LNs. The girls are always represented as their vtuber outfits in illustrations. Also the anime makes it clear that from stream viewer perspective, it is just live2d avatars moving around. And the visuals are basically an interpretation of what is being heard.