First of all, don't think like a victim! I never had time for my friends talking about "feminist" stuff, because I refused to believe being female was an issue. Technically, are females discriminated against with wages and mentalities of others? YES but the less power you give it the better in my mind. The misconceptions of others about women are not my problem. As far as racial bigotry, it will always be around. You let it get you down, or you acknowledge the bigot has the problem and move on. You teach your kids it's wrong to hate because of race/religion, or be cruel, or talk cruel and to recognize it when they see it.
Sometimes there are opportunities to stand up for people in skirmishes and votes, and you always should, but for the most part, going around "looking for bigotry" and dwelling on the perceived prejudices of others will not help you, it will only hurt you. Focus on the good people in the world, and not the bad, and teach your kids to be in the good section.
Afraid your kids will be abused by a bigoted person? If something is too abusive, it would be against the law, so I wouldn't worry too much about that.
When I'm in a position to be discriminated against (rare for a white person but it has happened) I feel the person acting that way has their reasons, be it fear or revenge or how they were raised-I don't hate and I don't let it get me down. What's my option? to get SO MAD that this particular person hates whites and really dwell on the fact that they dont' like me and may have been UNFAIR to me? Think of all the other people being discriminated against, realize it's a reality, and pick the right path for you and yours.
So for your letters
a) for your own bigotry, there is only one rule, don't judge people by race, religion or other superficial means. For other's bigotry, don't sweat it.
b) Combating bigotry? I don't. It's like all forms of evil, it will always exist. Well, we did leave a neighbor's house when they started saying racist things. I cheerfully said I didn't want the kids hearing that, and explained to the kids after it was not OK to show our approval of their mean words. So you can do stuff like that. If I was alone, I may have ignored it since my views are set and not vulnerable, but I had to show the kids it wasn't OK.
c) Show your children through talking, reading, history lessons, and how you treat others. Always refer to people of other races in the same respectful terms you use for all people. Talk to everyone the same way when you're out and about. I just read the kids a Joe Louis boxing children's book last night. It started us talking about blacks in America when he rose to fame, and Germans and Nazis (he fought a German opponent in one part during Hitler's ascension) and everything. The kids are only 5 and 3, but they know whites used to be very mean to blacks and some still are, and lots of people hate other people who are different, and there will always be evil in the world, but it's not OK. They already get it in scale to their ages. We've had many of those talks, and we'll have many more. You need to be their source of facts and ethics, and be open about it.
ALSO, at this age, you DO have to tell them not to meniton skin color or they accidetnally will! Don't just "not mention it" in an effort to be PC. It's natural for them to notice the difference. With little kids, you have to have the "Some people have light skin, and some people have dark skin, and some people have medium skin, but you don't say it out loud, and everyone is the same on the inside."
We were raised in an anti bigotry home, in a white rural area a lot like where we live now, and my brother and I never thought it was OK to judge other races or groups. It wasn't complicated to grasp because our parents taught us clearly. We were the only kids who played with a boy at school who wasn't "white" and we didn't learn until much later that the area we were in at the time was racist and that's why no one else played with him.
We live in an almost all white town at the moment (drag) and my kids have said, "Look, mom, a BLACK person" before in excited wide wonder. UGGGHH!!!! I had to explain it's not polite to point out physical traits....sort of a hard concept when they're little. We were driving in Philly and my 3 year old said, "Wow there are a lot people walking here....a lot of BLACK PEOPLE walking!!!!" I was like, "Yes, there are all different people all different places that's why life is cool" type thing.
We need to get out more often. I'd probably have less work to do on the topic if diversity was around us.