"What A Difference A (Third Of A) Day Makes"

Oops. looks like I jumped the gun (again)...

On the same message thread on the IMDb board about the Christmas episode where the ABC press release I mentioned earlier was shared, another poster (lynlyunderwood) later posted a link from Jesse Tyler Ferguson's (Mitch's) Instagram account, where yesterday he posted a picture from filming of the Christmas episode (with guest star Andrea Martin from the old Second City TV days).

So there will be a Christmas episode as expected.  What role if any Alex has is still TBA.