Not sure . . . but I would pull down the light fixture closest to the circuit breaker, to see if the hot wire fell of the fixture's connection point, and to test voltage continuity at this location. If all the other light fixtures are fed off this first light, and the connection failed there, that would explain it IMO. [if I have understood this right?
]
Good luck and please let us know what you find.
Peter
PS -- That's what you get for letting go of the FC20. [humor . . .
. . . ]
PS2 -- Removing the light fixture might be a real challenge if they are like our 2014 FC20. There are weird clips/springs which require a real tug down at some point. Maybe yours are different. I would search here in the blue box above for "ceiling light removal" to get some guidance. I found a thread or two last year, and will look if you want. Please advise.