Is 30,000 rounds really needed for PBKDF2?
Can I safely reduce the rounds to make it a bit faster? and if so what would be the minimum?
Could I get away with 10,000?

Anyone trying to crack your encrypted data is not going to be limited by the speed of javascript executing in a browser. They'll be running FPGAs or something much faster than that. So 20,000, 10,000 or 0 doesn't make any sort of difference here.
Where I learned this