A column that elaborates on how the filesystem handles tiny file data (of a few bytes, like 5) would be nice. I.e. does it waste an entire sector for it (or worse), does it store it alongside the directory entry (inside the directory "file"), does it store it inside the inode of some other file?

(This doesn't really overlap with "extended attribute", because that's just another tiny file and really, regular tiny files are as interesting) 
  12:
This is called tail packing  
And block suballocation, which is a similar concept. I am unsure about file systems that keep short files with the directory or inode entry. I've heard something vague about NTFS keeping short files in the MFT; if this is true, it indeed isn't represented right now.   
This is correct. Tail packing and suballocation put multiple files into one block, but that is still discontigous from any other related information, like the inode block or directory listing. By contrast, NTFS stores data for *very* short (I don't have an exact number, but it's in the several hundred bytes region) files in the directory listing, which entirely eliminates a seek for the data. Perhaps a note of this fact in a footnote for the "partial" suballocation support?