I've gone in and edited those to say Mathematics (Codidact). We currently don't have a way to automatically replace those when we launch a community, but it's on the list of things we'd like to automate when launching a new community.
Aside from the $sitename, the Math FAQ is currently pretty empty. It'd probably be a good idea to flesh it out a bit more; this means identifying what you'd like to actually have in the FAQ and then having a moderator / staff member edit the page. I'd recommend starting a meta discussion about what the FAQ should actually encompass.