Julian was so disappointed when they first learnt that Viola was a cello player bc she could have been a viola player. or at least a violin player. Julian complained for quite a while that Viola could dare throw away this marvelous opportunity to make her life more of a pun. they still mention it sometimes "Viola, it's not too late you can still learn to play the viola. Why aren't you taking viola lessons yet? If you're that against the viola you could still become Viola the violinist, come on Viola why do you hate your name?"
Viola chose the cello as her instrument partially to avoid jokes about her name but she's friends with Julian and that's not how you avoid that sort of stuff. she just bops Julian with whatever book she has and they shut up for a while.