If I tear down buildings as you indicated then you also get a penalty of negative population which would preclude any further building until the negative population is made up by further building nor does the rewards offer enough population to offset it. Instead of this new battle system, they should have allowed more expansion in the cities by now. I have buildings I can't even begin the place in my city. Also, you seem to be a bit cavalier with the expended resources it took to build the buildings in my city especially since catering now cost an enormous amount of resources one I checked today 15000 elixir 18000 silk etc REALLY????? However, I do appreciate your taking the time to respond to my post. Thank you, at least someone is reading these post, since I am sure the developers don't give a hoot! Cheers right , mate!
You should not have to tear down any other buildings other than older culture buildings to progress unless you have a disproportionate number of residences or production buildings or something. Besides, when you get the prize buildings, they go to your inventory, so even if you don't have space now, you can always wait until you have more space to build them. The event building are certainly worth far more culture per square than then current age culture buildings, so again, it's worth tearing a few down. I got Wonky Walter in Chapter IV, and it's 95 culture per square was more than well worth it to tear down two Cyclones.
It seems like you're at a higher level, but I'm posting this below for any newbies who happen to read this.
Tearing down older culture buildings and replacing them with other and better buildings is a good strategy in general for Elvenar. For instance, if you play Elves:
Spot of Whispering Trees
-available fairly early on in Chapter II
-12 squares of space
-400 culture points
-33 culture per square
Mysterious Cyclone
-available near end of Chapter III
-9 squares of space
-440 culture points
-48 culture per square
Temple of Ages
-available near end of Chapter IV
-20 squares of space
-1200 culture points
-60 culture per square
The culture per square is nearly double at the end of chapter IV than it is for early chapter II. Yes, it does mean giving up valuable resources when you sell an old building, but at least you get half of them back. The benefits heavily outweigh the positives since space is much more severely limited than gold and tools.