Some of the fonts were impossible to read without zooming on (the ballon like one specifically, the space inside characters is too small for this size and all the characters have similar shapes). Additionally, some of fonts had substantial spacing between lines, I recommend trying to bring it inline to the ratio the main font has.
Okay, so who's fonts specifically? Since I'm seeing the pages at the full size when I'm typesetting, I didn't notice how difficult some of it was to read. Also, since I'm so familiar with what they're saying, I didn't have a problem reading it at smaller sizes either ^^; Sorry about that.
Touru's is the default one I use "CC Wildwords" and I don't think there is an issue there
Tsubaki's (Star Kitsune) is called "Night in Toyko" and other than having to use the bold variant to thicken the lines, I don't think there's an issue
Nikka's is called "Puffy", which I think is fine?
Letori's is called "Masiku" and I did notice the font is kinda squished together. I did try to increase the spacing already, so I'll try to increase it a bit more next time.
Sarah's is called "Origicide", which might also be a bit too cramped? Not really sure there
Unna's is called "Dounut Monster-G" which is likely the one you mentioned being hard to read without zooming in, in which case I might have to just get a different font for her. I just wanted a font that was big and soft-looking like her lol
Sommeil's is called "Sunny Spell", which again, I don't think was an issue. And I really hope it's not, because I need hers to be similar to another character's font for plot reasons lol ^^;
All of the fonts I use are sourced from
1001 Fonts under the 'free for commercial use' filter to avoid any messy business later on lol