Editable text frame on master page (Yes, I know this sounds dumb, but please hear me out)

Hi, I am a comic book artist who's preparing my first-ever hardcopy book.

My comic book is an informative one, with fixed panels for every page, like this one below.

So I placed all the text frames, panels, page numbers, rectangular frames(to put my textless comic page) etc. on this master page.

If I place the images and texts, it looks something like this:

As you can see, I overrode each text frame to type in something else. Let's call these "main texts" for this post.

The thing is, what if I want to change the properties of these "main texts" throughout the entire book?

Let's say after I finished all the editing, I found the main texts too small and wanted to increase the font size. Do I have to do it manually for each page? Is there a way I can apply ONLY the properties of the text frames on my master page to its... "children" pages? (Sorry, I don't know the word.)

I did put all those main texts in one layer at least, but still, the book will comprise about 200 pages with these main texts, so if there is a way I can do it in a single action, it'd be very, very appreciated.

And another question, if you wouldn't mind, which font size would you recommend for the main texts? The book size is 6" x 9" (152.40mm x 228.60mm), and the main text will be in capitals only.

Thanks for your time, good folks! Have a nice day!

Bob