The bug with the cursor not working properly in full screen was fixed in an update shortly after the game was released. Although LDW have sent the update to other games portals, it's up to them if they decide to include it on their site. BF obviously didn't bother.

I can't say why the peeps don't interact with the dining tables or yoga equipment; there's other stuff you can buy which they also don't seem to use on their own, like the carousel.

Getting rid of the ants is a puzzle. If you want to see a spoiler, check this page, section 8.