The geometry calculation is currently approximate, not taking into account that the laser planes have ~3cm offset from center, that's one. Timing precision is probably the next one - microseconds might not be enough and we can measure better.

Currently std dev of each position coord in rest is 1.9mm.

Fusion with IMU is the next level and is usually done later down the line because it needs to be tuned for particular model. Yes, the drone does that.