Gracious! For that kind of footprint I'd want a traveling circus set of buildings that each expired at 45 days or more (I'd prefer the 100 allotted to the Genie). One building for each of the three FA map stages, 4x3 = mana, 4x4 = seeds, 6x5 = unuruium. Additional linked bonuses for increased amounts plus a chance drop when all 3 are linked (one of each). [Chance drop would need to include diamonds.]
Admittedly, I'm making an assumption on the expiring building since the OP said "ferris wheel", and that's an expiring building.