Tapping Hearts

Just some background...

Sometimes I visit farms (especially now, when it is required to complete goals), and of course I tap on the 5 big hearts floating over buildings. However, sometimes those hearts are floating above older, no longer active, former event-related buildings...for example, the Lunar Workshop from a few years ago (it looks like the current Noodle House, but in a blue-red-white color pattern). Recently, I've noticed other former event-related objects also "active" in the same way...such as the Muddy Pig. And on my farm, when other players have visited, I've seen the Golden Barn Birdhouse with a heart floating over it.

So, as a way to help players, perhaps we can create a list of "active" buildings and event-related objects that allow players to get hearts (and coins)? While this may mean little for new players who won't have access to these items, players who have been playing longer can put these objects out on their farms again with two potential effects, especially when we now need to visit community members.

1) more opportunities for all players--new and old--to build their social score by having more hearts available per farm (at least, more potential active items that can give hearts).
2) more opportunities for old players to collect coins from their visitors.

So, I mentioned 3. I'll do my best to test the older objects I have in my cellar, but if anyone else can add to this list, it would be much appreciated. Also, if anyone can confirm that these objects are active, it would also be helpful to know that it was not just a fluke or a glitch.

Lunar Workshop
Muddy Pig
Golden Barn Birdhouse