Looks like I'm one of those "influencer" people now. What a responsibility!

It’s eerie to see how Mio easily changes her mindset. First, she had no interest in joining the light music club, since she wanted to join the literature club (was it?). Next week, she is so into it that she doesn’t want the club to disband. Kinda felt a bit off.

Perhaps so, but it can be thought around easily by stating that Mio actually wanted to be in the band all along, only she was insecure about actually doing it. Remember that she does not possess Yui's crazy talents (e.g. discovering muting all on her own), but she is quite competent. That means, she excercised for years before the club's formation.

ps. I’m liking Mugi the most so far.

So do I, but to each his own. It is a well-rounded cast, so most can find someone to like (although there aren't many characters). The flip side is, those who would like to hate, always have a target too (e.g. the "retard moe" in words of Evirus).

As I mentioned before, Mugi is a small, but notable step forward from Miyuki. She is, most importantly, not inconsequential with her tea and cake.