"Is He a Fanta Drinker?"

I think its a nice, subtle way of asking whether Priests, Bishops, Cardinals, Religious Communities and Catholics in public life are loyal to the Pope and faithful to the Magisterium.

Just ask, "And what about ____________? Is/Are he/she/they (a) Fanta drinker(s)?"

Of course, the term, "Catholic" should really suffice, but nowadays there are so many Catholics in positions of influence whose words and beliefs do not reflect the Church's Teaching that it is really worth creating a euphemism.