A few considerations around question 1:
- A low pass over the runway is a non-standard flight maneuver in a non-standard configuration that little to no crews have practiced in real life or in a simulator. Most operators forbid the flying of such a maneuver as one can easily end up in low speed / high AoA / high thrust situations close to the ground (and remember: alpha floor is inhibited below 100 feet RA as was painfully demonstrated in France)
- ATC staff, or actually anybody, is not able, nor qualified, to assess if a gear leg is up/down and locked from the ground. Wrong assessment of gear position leads to false assumptions about gear position and safety (you could land with the expectation that the gear is safe and have a nasty surprise once on the runway).
No down and locked indication on wheel page or gear indicators after applying the appropriate procedure: assume the worst.