So I've been working on a sort of arts & crafts project in order to use my island space to it's best potential. I used tiny squares to create habitats, buildings and other structures in their various sizes (2x2, 3x3, 4x4). I then sketched an outline of the uppermost right piece of land (the biggest one). This pic isn't great so I'll try to list the 'resource' structures and how I pieced them so that all remaining spaces are 4x4 for habitats. I don't like that the one area is so jam packed, but it is what it is. I also had to sell off 2 Olympus habitats as they didn't fit in my design. I hope this helps other players
All 4x4 squares along the top and middle sections are regular habitats. Along the bottom, starting at the right side, the red squares are resource habitats (apple, bomb, map & dynamite). To the left of those are 3 nests and the noble crystal. Above and to the left are 7 farms (green squares). Above the farms are (from left to right) Stable, Evo Temple, Craft Shop, then 3 gold habitats (have since moved somethings around, but size wise this is accurate). Above that row are 2 reg habitats, Breeding Den, Breeding Roost and 2 more gold habitats. Then the spacing kind of shifts so above the dens and gold habs I have Olympus hab, diamond temple, spa and trade portal. Above those are 2 Olympus habs, Craft Shop and Ticket Temple. The remaining spaces are all reg habitats.
The only glitch in my system that I can see so far is if/when I fill all my spaces, I will not have a square for event collection items (such as the Pillar of Places we're using right now).