I`m in chapter three and so long didnt come across any race specific equipment, so the only difference would be the stat modifiers at the time of creation of the character, the favored class (if the game takes it into account, which im not sure and im too lazy to check the manual )
and of course the extra feat and skill points human receive at that moment as well.
Regarding a sorcerer or wizard in heavy armor, you are right, you could end up acquiring the proficiency, providing you fulfill the prerequisites, but always have in mind the HUGE arcane spell failure percentage armors come with, which would mean having a heavily hindered spellcaster.
And finally, regarding alignment, I`m afraid there`s not much I can help you with, just have in mind that it can be shifted during the course of the game with your actions. For instance, my character is Lawful Good. I got 85 points in lawful, and 100 in good. BUT I remember killing some NPC which lowered the "good" points to 70-something, and then had to bring it back to 100 with things like refusing some rewards, etc...
No action seemed to change the "Lawful" points so far.
Good luck and have fun