Is it safe to delete my Time Machine sparse bundle? Can a fresh one be recreated?
As long as you don't care about anything in the backup being gone, yes it is safe to remove the sparsebundle.

Disable Time Machine first. Instead of deleting the whole bundle at once:


Right-click and choose Show Package Contents.
Open the bands folder.
Select a large number of bands (8000 at a time seems to be good from what I read) and move those to the trash.
Repeat until all bands have been deleted, then delete the main sparsebundle file.