Please remove the population. 1-20 people tops. It completely undermines the building's lore. Also, the population, if it is to be left there, is way too high. For example, in IA the AA gives 980 pop when fully leveled. Houses taking up the same space in HMA would give 5 pop less than the IA AA*. This population is over the top. If you want to change it to happiness, go for it. If you want to make it provide happiness equal to the pop it provides, okay. But there has been such an influx of residential buildings that this is over the top.
Look, I get that population is helpful, but only to a point. We need more main event buildings that give happiness for the game to become more balanced. Currently, it is way over-weighted towards the population. This event is good, but I can't say I'll enjoy it because of the massive population imbalance. Definitely needs to change for this event to be a hit. And I can assure you, if it is changed, this will be an amazingly awesome event.
*Based off of the Town House, which gives 156 pop in 4 tiles. 25(156/4) = 975.