Wow, Fletch, you're quite something. I love that you took the time not just to visit all these parks, but really look at the detail and take notes. KUDOS!
I think my islands were at their best just after Panlong and the Chinese decorations came out. I moved a lot of habitats around yesterday in order to get more coins, yeah my panlong and my cold island islands are my money earners. Of course this could all be maximized, I could get rid of lighting and fire habitats (did you notice I don't have a plant habitat...gave up on that a long time ago). But I really need to draw a line somewhere to keep the game fun. It can't all be about the money, right?
The thing with the egg statue was a glitch at the very beginning when the game first came out. I had all my portals on the 3 original islands like that...it's kinda cool how the visitors come out of the Egg's column. Then, one day I tried to move one portal and the egg statue wouldn't go on it anymore. Bummer. Eventually I also needed to move the second portal, but the third (last) one will stay no matter what.