After days and nights research, I have got much progress on my FPV system. The first thing I got done is about the regulation. By using the DJI FPV system, I do not need a ham licence as the DJI fpv is using 5.8g transmitting the image.
Second, thanks to the people in the DJI Canada store (the one close to A and J hobby), they have made me a cable that can directly connect the air unit with the battery. By having this cable, I do not need an air control unit ( and DJI controller) to power up the air unit.
Also, the people in the DJI store makes me a 1 to 2 power cable that I can power both my air unit and the plane by one battery.
Finally, I went to A&J hobby and got a frim for mounting my air unit system to my plane and figure out how to run the cable.
hopefully, this week can have some good weather (seems unlikely so far), and I am looking for to test my plane.
Thanks for asking and posting all this. Really good information. And good on DJI for the help.
Follow up, today I went to the field and tested the load of the plane. Feels fine. Need a better way to tight the camera on and find it a better angle. Sadly I do not have an sd card at the time, so I can not record the video(I did not use FPV. I only to connect the power on the cam and test the load) later I found one in my car, and I was already on my way home.
feel confident to fly this plane and hope there is better weather in the next few days.