Sorry for the late answer :/
I don't really have a tilemap to share specs with. Everything can be dynamically adjusted, the real problem lies in padding/margins etc.
The Japanese characters can become off-center because of the different heights. I would greatly appreciate it if you could bundle your aforementioned tilemap in the salmon-family.zip file.
Thanks for your recommendations. It felt like I already searched through the entire internet, but I hadn't seen these before!