Your point three is what Id like to do.
The content is available on the homepage (desktop breakpoint) but it is contained in tabs. (See image)
On the mobile breakpoint the “tabs” are hidden but I have added a mobile menu which allows the user to go to the content of the tabs as individual pages, for example “Ralph Stratton” page. It’s these pages that are not on the desktop Navbar so can’t be linked (as you suggest) but I was worried that they could still be found via google as I seem to only be able to hide a page across all breakpoints or hide sections only.
So … your point three "If you need to hide pages from desktop or mobile, and vice versa, hide the links that are leading to those pages.”
The links are hidden … BUT will these hidden desktop pages be able to be found or seen?
I guess I could always make them presentable then if they are found “randomly” they would not look a mess.
Hope that makes sense