When I started decorating my island I looked at what furniture I had in storage and tried to imagine what sort of areas they could fit in. Then I did little builds at a time. I still have plenty of empty space but that means I can still expand and build whatever ideas I have in the future. And...
Hamlet, Phoebe, Stella (<3 <3 <3), Wendy, Pudge, Zucker, Whitney, Sprocket and Zell
Oh and there's Naomi too, she refuses to move out though despite all of my attempts.
You unlock it after completing the "story", so if you're not very far in the game then it'll be maybe a week or two away? Idk it's been a while since I unlocked it. If you really don't like playing on your island then it might be a good idea to restart.
You can always change your layout with terraforming (which you unlock a little further in the game) and I'm certain there's tons of people on this forum that would be willing to give you other fruits that you could use to replace all those pear trees. ;)
The only thing you can't change is the...