I find it best to create an 80 Gb partition for 'root' ('/') and the rest as /home. Doing it this way, should the system go south all you need to do is reinstall the system to the root partition, but you have to mark /home as /home but not format it if reinstalling. It is also best to have a separate /home (which can even be on a separate drive) for Timeshift snapshots.
No, isn't needed. NTFS is for Windows Drives.
Yes, is a Point. But when You want to keep it simple, I would let it on these 2 Partitions.
Grateful.