"diversity" imho is overrated. You want diversity, send your kids to UC Berkeley. Then after all said and done, he/she could end up either a great scientist, a great lawyer, a great biz person, a great doctor, or a wannabe hippy, or the unabomber.
Seriously though, I wouldn't be actively seeking "diversity". When it's all said and done, people are people, doesn't really matter what multi-cultures bring to the table imho. If you live here, you speaka american, you live american, you talk american.
We don't speak the queen's english, heck we don't even speak the aussie English. We spell say color instead of colour, flavor instead of flavour. I guess it could be worse, we could suffix everything with "ehh", like our brothers to the north. Yes, I know some of us need to become aware is there is another country to the north of us…We use our measurement system instead of the metric system, of which even the UK has now pretty much abandoned. Heck, some folks don't even know the difference between SAE and metric, and end up stripping bolts by using metric wrenches and SAE applications and vice versus. Rather than think about 1 to 100, we think from 32 to 212, and since most of us suck at math, we can't figure out when we're traveling abroad what (F degrees -32) *5/9 in our heads is with whipping out the graphing calculators and laptops we buy from China to cheat on our calc BC exams. We pioneered the fashion of jeans that look like they've been through a tug-a-war. We've figured out how to land on the moon, but can't figure out how to prevent accidentally delivering nuke heads to Taiwan and not noticing for months, until the Taiwanese ship the delivery back to us. We spends hundreds of dollars on gym membership, but yet spend 15-20 minutes driving around a parking lot trying to find the closest parking space, even in a clear sunny day. We're deep in debt, yet we find the generosity and compasion to help other desolate countries in terms of volunteerism, philantrophy, etc.
And yet despite all the quicks and all the things that make you go WTF, you find that on thing that's different about this country from all the rest. Americans are creative, they're individuals. It's probably why you still see so many nobel prize winners from america, why some of the best athletes are still from america, and despite what some may think, one of the best places to live. It's why you can do chinese one night, italian the next, mexican next, and french the other day ( yes, I'm talking about food, and not relationship conquests). It's why in in this current election year, you have a three way race between a woman, an african american (though he's really not african american), and a senior citizen that refuses to retire. And while folks might not like all the candidates, you have to say it's pretty "diverse" this time around.
That said, I think the only thing you really need to teach your kids about "diversity" is respect. Respect for people being different, respect other people's customs and idiosyncracies (I can't spell. Heck I'm american). And more importantly, respect for our freedoms that occasionally we take for granted.
