Yes. They have a clip attachment (not included) to keep the probe off of your grill grates.
Probe is probably 4-5 inches with a bend 3/4 up the probe. Not sure how long the core is.
Bluetooth is outside the grill entirely. The probe is the only part in the grill. So yes, it will work with any grill.
This unit only has one port for one probe. There is another igrill that is larger and takes at least 2 probes. Not sure if it has any more than 2 ports.
I would think so. If it can take the heat inside the grill, I dont see why it wouldn't handle the heat of oil.
Just the probe. I dont know how hot the unit could handle if placed in the smokehouse.