Yes that is the type of freewheel that I used, however I used a 14T your pic showes a 16T.
The freewheel only comes into play when you are pedaling. So I would recomend the very highest tooth count you can find.
The motor ratio that I have is this: 16T 10T 14 thru 28T(rear freewheel cluster). You should be able to find a freewheel adapter for about $7 to $9.
Oh yes you not need a freewheel on the motor side, the one in the pic is tack welded so it only functions as a standard gear.
PS: gas tank is in seat bag.
That info should be on this link
I am interested in building the same set up for the Schwinn Chopper as you have posted on your build. You did an awesome job with the jack shaft and I would like to replicate this for the OCC bike build that I am starting. Could you give me a list of parts and possible suppliers? It would also help if you could let me know what size sprocket went where. This is such a clean install.