wifi are pretty wide spread in dash / handlebar cameras today, but it are still pretty slow, you are not going to get the same experience like at home connected to your router.
Event sensors like G sensor are also in most cameras, it will ensure the event is locked in a read only state, but the camera are recording all the time, so with a reasonable sized memory card, you will have to drive for many hours after a event before it is the oldest and get deleted.
For recording after a event you are better off using your phone, you can not detach a dashcam and walk around and film with it, the ones that have a battery, just like the capacitors it is just there to finalize last file in a major event, it is not there to power the camera for any length of time, the lipo batteries also die pretty fast as they do not like excessive heat or cold.
2 sperate cameras can be done, but i would not bother in this day and age, most if not all MC cameras are also dual camera these days.
Some cameras do have a screen on the main unit but it is just for doing settings ASO, it is not a good OLED screen but rather cheap LCD screens so would be garbage in the sun anyway, better to hide it all and be sneaky.
Most wifi cameras, you also have to turn on the wifi, it is not like they boot and the wifi are just on so you could automatic connect to it like BT. wifi on also generate heat, which can be more of or no problem depending on where you are.
I think we are past it now, but not long ago if you turned on wifi in a dashcam, the system would lower bitrate ( image quality ) to be able to handle that extra load of having wifi on, but i think thats done for now in systems using modern hardware.
As for mounting, you waqnt to do that of something very rigid, or you will have shaking / jello in the footage, so sticking that camera to your fairing,,, thats probably not going to work.
