Q: landsize is in diffrent sizes, and to that it also differ how much things you can place outside, but if you skip all extra things can you put a Large size house on small land even if you can skip all extra things?

Patchnotes fails to include these details, also with this taken from live letter IX, it could mean its possible?

Q: Can you expand to an M size or L size house from a S size house?

A: You won’t be able to make changes like this when it is built. You will have to build a new one on open land.