You ask some pretty good questions and i'm glad you said opinions, that way I can hide under that.
Here's a few of mine:
"What do you do with children? Especially children in the public school system? You know at school they have parties, dress up etc." -- Part of what we are learning as mature Christians is that while we are in the world, we are not a part of it. This means not partaking in anything that is contrary to the ways of God. As far as I know, up to now it's not mandatory for children to participate in these parties. As a child in public school, my school would have Christmas parties and plays, etc. I remember the little Jewish children being excused from these and they were not resentful in the least. If anything, they were secure in knowing that they had a strong commuity backing them up.
"How do we make choices like that for our kids? How do we explain our beliefs in a positive way?" Christianity has never, ever been about popularity. Our Lord told us that when we would be despised and persecuted for His name's sake, we were to remember that He was hated before us. We explain to them about the BIG picture. This life is to be enjoyed in blessings that come from above, but ultimately nothing is above our eternal salvation, and this is the price we pay. Besides, the blessings of obedience are always over and above any sacrifice we might have to make!
"What happens when they are teased for not partaking? or worse yet teased for their beliefs?" Again, look at Jesus, the author and finisher of our faith. Being teased by your classmates is not the worst that can happen. There are countless of Christians around the world who must endure torture and persecution just for gathering to pray and read the Bible. And yet these saints continue to do so, counting it all as trash and considering their pain as blessing. It is this same spirit that has driven the martyred saints to sing hymns while being put to death. I imagine if they had considered being giggled at by silly school children a real obstacle to faith, they would have never been put to death. But in whose eternal body would you want to be? How would you like your children to respond to a major challenge of their fatih? If they can't learn to stand strong in the little things, they will never stand in the greater trials, and even worse, they will depart from the faith under the slightest pressure.
"How do we make these decisions for our kids while effectively portraying the wisdom and light of Christ?" Nothing in the world speaks louder than love. The love, support, values and security that GOOD Christian homes offer their children, is the greatest deterrent towards any outside adversity. You love, support and understanding teaches by example, more than all the rules and regulations in the world. A family unit that talks these things out, making no compromises withthe Word of God, but accompanied by hugs, kisses, encouragement and the sure promise that "we as a family will stand together no matter what", already gives a child an edge over anything that may try to discourage or pull him astray. If you look at the cultures where strong traditions are kept by families, you will see that there's very little dissent in the children, It isn't the dogmas that holds them together, it is the strength in unity.
And not deter them or their friends from Christianity? Like everyone else, their friends will have to come to the Kingdom of God through repentance of sins and faith in the atonement of Jesus Christ. If they are coming in because it seems like a fun social club, then they are joining the ranks of the mislead into the wide path. We are the salt of the earth, but if we lose our flavor, then we are nof no use to the Kingdom of God, although we may be ticlking ears and stroking flesh..
There are 364 days in the year that are not hollow ween. 364 days of opportunity to have meaningful and exiting times with your kids. You can make/get costumes for them, throw parties, provide oodles of fun, all in ways that provide the things they need to grow as healthy and strong adults, while learning the value of obedience to God, and to love Him with all of our mind, body and soul.
Finally, brothers, whatever is true, whatever is noble, whatever is right, whatever is pure, whatever is lovely, whatever is admirable—if anything is excellentor praiseworthy—think about such things.