totaltec

That’s a lot of questions for one thread!
I’ll tackle #5.
5) How do I change my primary font size?
In your child theme’s style.css, try adding the following:

.entry-content {
  font-size: 12px;
}

This should set all of the text inside the main portion of your pages and posts to 12px.

What permalink? Do you mean all the permalinks, or just one in particular? Have you checked your .htaccess file?

I just view the page source, and use ctrl-f to search through it for “wp-content”. If that exists you can be sure its WP, and if it doesn’t exist, and they are using WP, then it is so highly customized that it doesn’t matter. ??

If you want to search what a site is built with just try https://builtwith.com
That will tell if it is WordPress, and whatever else they might be running. They only index medium to large sites, and they are only right about 90% of the time, which to me is still good.