Are candles too dangerous with kids around?

I wouldn't think so. But you can always do tea lights in a glass jar so you get the same effect without the danger of them being knocked over or having children touch them.

Each of my center pieces will have 4 different size votives. I don't think it's dangerous with kids. It's a wedding they shouldn't be "running around" especially by the tables maybe on the dance floor

I don't think so either, I would either do tea lights or higher containers or lanterns

In my venue the flames need to be contained anyway so check your venues policies

They should be fine! But, you could always get the flameless candles if you'd rather play it safe