The cursor affinity could be entirely subsumed by the visible typing attributes, which might be more intuitive. For both, I'd worry about the user's cursor configuration affecting things - it could be safer and more widely compatible to have it float nearby rather than have it attached to the cursor.

The link editing doesn't seem like an improvement on other rich text interfaces, with no visually obvious way to edit the link destination.

A keyboard shortcut that tells you other keyboard shortcuts isn't at all innovative, but it is handy and more software should have it.