There is also this regex that I use, but be warned again, this will find (nearly) every single hyphen... and takes forever to click through the entire book one by one.
This is why I initially recommended the Sigil Spellcheck method.
Search:
Code:
([A-Za-z])-([A-Za-z])
Replace:
This will work on hyphens like in my Case #3 above.
And again, I like to stress... SAMPLES SAMPLES SAMPLES. They really help everyone figure out what you mean, and allows us to help better.
As a side note, I use a variation of this regex to handle adding en dashes between years/page numbers:
Search:
Replace: