In the interest of giving credit where credit is due, my avatar is a scan of a hand-drawn caricature by cartoonist Jim Naylor which was done at my company's 20th anniversary dinner.
(Sorry about all the Fortress questions; it's been on my mind lately).
If I have a Steward and a Fortress in my hand and I choose to trash two cards from my hand, can I trash a Fortress then return it to my hand then trash it as my second card for Steward, or do I have to choose both cards before the actual Trashing begins?
My money is on the latter, but I could see it being the former as well.
This is covered in the Dark Ages rule book.
Dark Ages Additional Rules wrote:
When two or more cards are trashed at the same time, as with Count, first trash them all, then pick an order to resolve things that happen due to trashing them.