[puddleglum]

Interesting idea but honestly I think you are being totally unrealistic about what you can accomplish for under $10k, if I am understanding all that you want. Are you wanting to pull 400lbft torque from your electric motors in addition to your gas engine?
I will throw out some thoughts to consider, but please understand I have no first hand experience.
Did Chevy make your car with a 4WD option? If so, maybe you could find a parts car to adapt parts from. Are you thinking of having the motors direct drive to the wheels?
Do you have room to mount both motors end to end and still run cv driveshafts to the wheels? They can't be hub motors. I really don't think they would be the best motor choice anyway with all you want from them. One would be okay through a diff. but series motors don't regen. well which is on your wish list. Yes they have high torque on start up but if you run them direct, they will be running slow all the time and probably will overheat. I think controlling them to get even torque will be a nightmare as well. Series motors don't self limit their max rpm so if you ever spun a wheel on a slippery spot it could overspeed the motor and do damage. A single motor through a diff. would be easier and cheaper. The brushes will be wearing even when the motor isn't being used and if you do use a diff, you need to be sure you gear it so you don't over speed your motor at top speed. AC motors are much easier to control and will do regen, but will cost even more and finding low speed/high torque motors could still be an issue. If you lower your performance goals, you might be able to fit hub motors to the rear wheels but they likely won't have the torque you want.
When you are talking battery pack you need to pick batteries that can deliver the high currents you want as well as the range. Once again more power means more money. High quality lithium will be a must.
I think anything can be done with enough time and money, the question is how bad do you want this?