The crash thing, no idea.
On the race selection, it's on the world map that it's done.
1/ To check what race your selected civ is, hit tab again a few times to get the list of the races (the one with the red ---, WAR, all that), the race at the top is your race.
2/ Hit TAB again to get a list of all the playable civs where you can change your civ.
Go back to 1/ to check the race, until you get the race you want.
If you only want to play succubus in a world, only enable them as playable (disable the "Fort" token for the others in the launcher before making the world), and all the proposed civs will be for that race.
Hopefully, I explained well enough.
EDIT: @Zach: never edit the raws manually when it can be done in the launcher, it can cause troubles later on if you don't do it correctly.
Just uncheck the "fort" column for the other civs in the launcher, it does just that too.
