Certainly never any need to apologise when you’re spending your own time to try and help someone! 
And guess what? You were spot on. Reinstalling monogame from the same installer I downloaded a few days ago simply fixed the iOS projects entirely. So, order is very important! For anyone who runs into this problem and needs the fix:
(the following steps have been tested on the latest os x high sierra)
Install XCode first (and possibly run it so you can set your appleid as dev etc - I did so maybe important)
Install mono framework (not monogame, mono)
Install visual studio for mac, MAKE SURE all iOS options are ticked and enabled! Double check!
-if at all possible create any test project at this point to check that Xamarin.iOS references are working properly, if not run that visual studio installer again because its a finicky bugger!
NOW install monogame. Dev branch! You don’t have to compile it yourself (i did not) but grab latest dev version and install that.
You should hopefully now be able to create monogame apps for iOS, enjoy!
Sadly my DesktopGL portable desktop projects are still failing to run (but compile fine) for os x with SDL2 throwing an exception and failing to load. If we can find a fix for that I am home and dry