Would have liked to see trichome pictures. It is difficult to assess the differences. I'm more interested in the washing technique, that bud looks very "clean" but the before is farther away and hard to compare. Is sounds like you have adopted washing as a standard practice. Did you notice a...
For seeds, there is no set rule. Time, height, & strain are just a few of the many factors that can be utilized when deciding to flip seed started plants.
I have read either can go from veg to flower. It is a matter of yield expectancy, I believe. As far as when to change lights; a retailer's suggestion if bought seeds, is probably your best bet.