I think you can, just put your 2 channel system on zone 2. But you'll be better off to have a better amp for your 2 channel system.
Not sure why you want to use different speakers for your HT system. Your 2 channel system will likely have better speakers so it is common to use them for the front 2 channels of the HT system. To do this is simple, you just need to take a pre-out signal for the front 2 speakers from your HT reciever to a seperate input on your 2 channel amp. You just need to make sure your 2 channel amp has an extra input.
If you have a different reason for doing it your way I apologize for the distraction.
Jerry