Hi again, Kristina! It's great to hear back from you! So the good news is that nearly all of the longhouses have undergone extensive renovations this year (with Rapa Nui and Tahiti still to go). This means that you don't really need to be concerned about which longhouse you'll stay in since all will have undergone refurbishments by next September when you plan to visit.
That being said, I would recommend that you visit the online
Polynesian Resort profile page to view the interactive map (with zoom feature) which shows the location and names of all the longhouses. This may help you to decide which specific building location you'd like to request. For example, perhaps you'd prefer to be close to the Nanea Volcano Pool or to the dining options and Resort monorail platform located at the Great Ceremonial House. Or maybe you'd like to be near the Transportation & Ticket Center for convenient access to the direct monorail line to Epcot.
When you make your resort reservation, just ask the Cast Member to note your preferred building request on the reservation. You can also call and have a request noted on your reservation at any time up to your arrival. Disney's resort room assignors will do their best to accommodate your building request based on availability, but please be aware that requests cannot be guaranteed. Also, certain room types are only available in select longhouses.
My go-to online resource for the Polynesian Resort is the independent website
tikimanpages.com. This site is loaded with detailed information on the Polynesian, including excellent descriptions of each longhouse with pros/cons in terms of location, views, room types and more.
I hope I've answered your question, but please don't hesitate to write me back if I can assist you further with any aspect of your vacation planning!