If RaceShieldFX is off, the shield color will reflect the strength of the shields rather than the race the shields belong to.
Ive noticed that Space dust doesnt do a whole lot in the game, which really it shouldnt, thats what that Navigational Deflector is for, but if you set that to 1, Space dust may do damage again, not sure, havent tried it.
UI type, well thats the User Interface, but I doubt theres any race specific User Interfaces in the game as yet, I seem to remember Dave posting his concept for a Rommie UI shortly after the beta patch was released, but the context of his message seemed to indicate that it might be included in the final patch, but not the beta.
Shipstacking you got right on, Target Direction, I want to say thats the default camera view, which never changes when you change it inside the game ANYWAY, I think F3 was a hardcoded default and that option is just redundant, but i could be wrong. Heading display might be along the lines of the UItype, it might do something, but because Taldren was rushed to get it out the door, it was never completed, and might be completed whenever ATVI gets off its arse. Another possibillty, is that Heading display might bring up the Arrow that points you in the direction you are supposed to go in the Campaign missions, the game might set that to 1 for those missions automatically.