What is meant by “courtesy”?
If a courtesy title is defined as a title without any privileges attached to it, then all of the royal family’s titles, besides Alexander’s dukedom of Södermanland (which has property attached to it), are courtesy titles.
If a courtesy title is defined as a title that is not legally recognized, then I don’t think any of the royals’ titles are courtesy titles. The HRHs have been allowed to use their royal titles in some, though not all, legal documents (including marriage contracts and driver’s licenses), and I assume the non-HRHs will be permitted to do the same.
Since there is no Swedish tradition of distinguishing between “courtesy” and non-”courtesy” royal titles, I interpret the 2019 comments from the Marshal of the Realm to mean that the grandchildren’s spouses should not be called (or call themselves) Prince/ss or Duke/Duchess, period. (Of course, there is plenty of time to reconsider that decision.)
By the way, does anyone know the exact words of his comment? Expressen paraphrases it as
Deras titlar kommer dock inte att föras vidare till deras framtida partners och barn (Their titles will not be passed on to their future partners and children), but it is not a direct quote.
På måndagen kom kung Carl Gustaf med beskedet om stora förändringar i det svenska kungahuset. Kungen har bestämt att fem av hans barnbarn, Madeleines barn och Carl Philips barn, inte längre kommer att kallas kungliga högheter. Barnen kommer att fråntas apanaget och blir inte skyldiga att...
www.expressen.se
It is clear that people differ in their definitions of “morganatic”, but wouldn’t your definition exclude nearly all marriages that others refer to as morganatic (such as Countess Sophie Chotek to Archduke Franz Ferdinand of Austria-Este)? In most cases, if a spouse does not share their marriage partner’s title and status, it is because they never had a legal right to it.