Yes.
A ground may also be needed. (rj12 pin 5)
Did you configure the V2's internal settings like in the .pdf in post #9?
Yes.
These are an alternative or addition, your choice not necessary w/serial.
No.
Each AD set has a positive & a negative.
The AEM's white wire is positive & the brown is the negative.
Choose an AD set and connect them accordingly.
Example: AD1+ = white wire & AD1- = brown wire.
Select that AD set's voltage pid then you can make the calc_pid for Lambda/AFR.