D6 I don't know about the 10 hours in a light twin. I only did a initial type rating and used that checkride as an ATP flight test.
You can do it [the ATP checkride] in whatever you want. But if you intend to do a bigger type rating in the future you might as well do both at the same time and save money.
The Test can be done in a ZFT simulator.
I got mine without actually flying in a "real" aircraft.