“5. The tall, combustible grasses grew right up to the edge of Lahaina.”
The G00g1e Maps satellite view along at least one street at that edge (Kahoma St.) seems to show a homeless camp in those tall grasses. That street was mentioned early on as needing evacuation in a timeline summary I saw somewhere.
https://www.google.com/maps/@20.8914727,-156.6812708,45m/data=!3m1!1e3?entry=ttu
One early report said the fire was man-caused by homeless camp cooking.
Interestingly, we have a man-caused forest fire here in Hayden, Idaho (now 2,500 acres) with suspicions of a similar cause.