Use GPT. No more 4 partitions limit and extended partition fiddling when risizing or moving stuff (that means UEFI for booting, if your computer is old you might have to spend some time in the BIOS to set things up).

You can resize live from windows (since version 7 I believe).

I'd use an NTFS partition to share files (because fat32 don't have enough prevention loss measure to my taste). NTFS partition access requires much CPU cycles though.

https://imgur.com/a/QnyCdc3

I don't remember why I still divide /root and /home. Must be a habit.

You can use NTFS, with ntfs-3g on the Linux side. I've done that and it worked smoothly, if rather slowly. FAT is just too 90s for serious use.

You'll likely want to continue using a native Linux fs for whatever you don't need to share.

Dunno about quality of any Ext drivers for Windows.

As for partitioning, back in my day people just slapped another primary partition. It's not like Windows supports Linux LVM.

Just use a ntfs partition for sharing files between Linux and windows.