You literally can do all of those things, you don't need permission from Hickman, Weis, or anyone at WotC to make whatever changes fit your table better. I've ran DL games a few times and made a bunch of changes to lore and rules to fit what my players wanted. Since you've mentioned racism, I wasn't a fan of the insinuation that gully dwarves were the result of gnome/dwarf inter-breeding so I omitted that part and made them just regular dwarves who due to poverty were uneducated and dressed shabbily but still street smart so the bad guys tended to underestimate them. They were capable of understanding important information and helped the party quite a bit with learning the layout of Xak Tsaroth and where the important stuff was located. The party needed the info so they didn't treat them as inferiors. Easy fix to something I wasn't a huge fan of. My changes might not fit your table and that's fine.um you quoted my changes... change the pantheon grouping, the alginment axis of the tower and the here I will copy and paste...
the racism/sexism right out for a game (it's okay for a story but not a game we are expecting to play with different people)
from a story point of view some minor tweaks would be enough... change 'good' and 'evil' to light and dark, and make some evil in the light side and some good in the dark side... then do the same with the wizards align the towers with the moons but not a concept of good and evil.
add an option for the DM to insert other races, it doesn't take much more then a page to show how you can include any/all races.
Anything published should always be looked at as just a suggested starting point to craft your game with.