Two hot wires, and two grounds, per seat, but both seats can use the same power and ground for the same use.

One set of power and ground for the seat movement, I'd make that battery power so you can move the seat with out the the ignition having to be "on". Generally, the power comes in on a center post, and the button directs which motor gets grounded to work, for each seat.

One set of power and and ground for the heat, I would pull that of the acc side of the switch, you don't want the seat heaters on if the car is not running. Should be simple power on or power off, but it might be separated between butt heat or back heat per seat.

The restraint system you probably don't want or need.