Is my HVAC system one or two transformer based?
Your system only has 1 transformer, at the furnace

Given what we know (that the cable with the red wire back-wrapped at the junction point goes off to the outdoor unit), we can tell that the orange wire from that cable is tied into the Y connection (orange wire) from the cooling thermostat and the Y connection (yellow wire) to the furnace as well.

This means that the other (black?) wire from the cable to the outdoor unit must be connected to C for this to work in a one-transformer configuration, and indeed, it connects to the blue C wire going off to the furnace.  Furthermore, the red R wire from the furnace goes out to the red wires in both thermostat cables, which is also a sign you have a one-transformer system.