Thanks for the feedback, I noticed the rooftiles too, to solve it I will just deform the island so its square. I didn't think of rounding the roofs yet that should add some more realism for sure, thanks for the tip. I'm tired of messing with meshes for now though haha, going to keep these for now, and re-import the meshes when I fixed the remaining issues.
I just discovered snippets btw, this is going to be extremely usefull to place my meshes.