Don't really see what purpose announcing restocks would serve, at least in regard to the houses. They're so few in number, some only getting 1 added, and the most bountiful only being 4. By the time they made an announcement post, the restocked item would already have sold out, as has happened a few times already. Having advance knowledge is going to do little to nothing to aid anyone with such limited quantity.
Not to discourage anyone trying for these, keep up the effort if you truly want it, but I would advise against setting one's hopes too high. At least thus far, it's not like the fragments or plush collectibles from last year's Fair where they'd add 10 or 20 or more per restock.