Oben RP-20 Quick Release Plate

Yes, the smaller moveable pin should be toward the front of the camera and lens.

No, the following plate will fit; https://bhpho.to/35uT72o

Is a safety pin to lock in the camera position and prevented it from twisting. Certain cameras provide this option next to the built-in 1/4-20 threads.

Oben Quick replease plates will only fit on Oben tripod heads. Every brand of quick release plates is different and unique from the next brand, and in general there is not a universal type plate in this instance we could offer you. The fitment on the Steadicam Smoothees are proprietary and for specific small devices, and as such, they do not offer any type of connection to mount an AHFG20 camera to them.

Almost a 2 in. square. About 1 13/16 x 1 14/16

It can probably hold the weight but I would highly recommend against doing it because doing so would by-pass the safety feature of preventing the screw from unscrewing when the d-ring lays flat. In other words, if the d-ring is standing up the screw may come unscrewed.