You are correct that neither replaces the other.
To fly under 44809 you require TRUST.
To fly under Part 107, you require a Part 107 remote pilot cert.
But you are incorrect when you claim that a Part 107 pilot operating under Part 107...
I Think, You will be able to purchase existing stock because the ban will only effect the importation of the Drone NOT the sell. If the stores "existing stock" is in a warehouse outside the country....Thats gonna be a problem.
If you are gonna...
That's the status of obstacle avoidance in each direction. Red means it's not activated, too dark to work, or not in the air yet. White means on and working.
You need a TRUST card any time you operate an RC vehicle that flys...Commercial flight or recreational you must have a TRUST card on your person. A 107 cert. does not replace a TRUST card.