Using these:

http://pastebin.com/DRd8c2mm - Island 1
http://pastebin.com/a3waCTnC - Island 2
http://pastebin.com/3e2WyFHw - Island 3
http://pastebin.com/4SsZyEMt - Island 4

I made a Monotype Teambuilding Guide of sorts, showing the order Pokemon or their prevos are first available by type. It also gives a visual of the type variety in Alola.

>unrevealed Pokemon are placed under every type I've seen people suggest, no matter how ridiculous
>presumably the order isn't 100% accurate as Tapus are probably uncatchable until later, some may be in an area on the island that is inaccessible until later, etc.
>Pokemon of the same type adjacent to each other in the Dex are grouped together since they presumably appear in the same area (obvious in the case of Rufflet/Vullaby, Drifloon/Misdreavus, Petilil/Cottonee, etc.) or in adjacent areas
>Type: Null is presumed to be a post-game gift due to its absence in the regional Pokedex
>Poison may seem like the biggest loser at first glance, but it might actually be Ground that earns that title in the end