So close. All done except finding the 2 entries that need a letter erased/changed, although I do know what the spots designate. I've found a couple of thematic entries that don't need any changes. (Not at all familiar with the theme, but wiki answered most of my questions).
One grid entry is a synonym of the 'hint', and after treatment it is synonymous with what the thematic characters do.
For the final change, I did a quick search for the obvious (nearly all of it's there, so it didn't take long to spot it).
I've completed everything in this puzzle to the best of my ability, but I am still left a little queasy by the word "map" in the preamble. I've put a dot in the middle of the three clashing cells and a dot on the cell wall between where the 4 omissions occur. Should I recognise the resulting "map"?