yes. the details are on their website, under commissions. My own analysis suggested you need 300k or 1M volume/month to breakeven depending on the product/exchange, then you start getting rebates.
Yes they do. I don't do much volume and I have been getting nett positive commissions on some options trades. I have not bothered to look at which exchanges as I am a swing trader and view commissions as a cost of doing business. There are bigger fish to fry.
I think even forl low volume retail traders, IB does offer tiny rebates for adding liquidity. I rolled a CMG March 515P and 595C strangle up to 555P and 610C. Each leg had a rebate of between 9 and 16 cents. At least there were no commissions.