NTFS is the standard for Windows. Nowadays Linux can handle reading/writing NTFS pretty well, but you should probably use the very established ext4 or maybe btrfs for its partition.
How about a used Thinkpad? Like the X280. 12.5". Touch. Depending on your region you can get a pretty good deal if you are OK with some scratches or other faults
Discovered beets a few weeks ago. Tagging, organizing, converting, … You can specify all of it in a config file and just add a new album and it handles everything for you