The exterior work shown in your picture is unrelated to the M&G project taking place inside. It is not necessary to shut down the entire Expo Hall because the M&G will not occupy the entire building although it will take up a large portion of it.Well, you'd think they would mention that in the "news and updates" section, which they don't. They would at least go into detail on the Expo Hall, if not provide any pictures. And I'm also wondering why they've opted for Mickey and Minnie to appear in Tomorrowland, of all places.
And there is a picture of the Expo Hall, from the outside. And there is a decent-sized construction wall next to the building, but it's from a distance, and it could very be just a simple touch-up job and nothing more:
Has the Expo Hall officially been shut down? Because it's hard to tell from the big construction wall here.
The Tomorrowland M&G for Mickey and Minnie is only a temporary measure until their new spot is ready in the Expo Hall. This was probably the most efficient location in a logistical sense for a temporary M&G for two very popular characters.
The Expo Hall M&G is actually old news, but, like most character M&G news, it hasn't been heavily discussed. I'm sure it's impossible to get pictures because the project is indoors with no way to peek over the wall. Our reliable insiders have assured us that Disney is putting in a good effort toward making this venue nice for the mice. And that is probably all they are allowed to tell us. The collective track record for all of our insiders is solid. I'd trust them.
As for myself, the destruction of Toontown Fair is bittersweet. I quite enjoyed the houses, and I'm sad to see them go. I'm glad I took a thorough tour with lots of pictures last summer. On the other hand, I'm eagerly anticipating the FLE; so, I won't miss Toontown Fair terribly once that is finished.
I don't think you can consider Mickey and Minnie homeless once their houses go. The guests in pre-Toontown DL and MK didn't perceive it that way. Like someone said earlier, their new home will be Main Street.