Any question answered...

It's not so much about the friction. A turbulent boundary layer wraps around a cylindrical/spherical body a bit before separating, which reduces form drag -- which is generally much larger than the skin friction. Making the body surface rough (or dimpled like a golf ball) to encourage a turbulent BL would increase skin friction, but it's worth it to for the substancial reduction in form drag.

But that doesn't mean you always want turbulent boundary layers, It just depends on the best way to avoid flow separation. I'm not sure not much this really matters when it comes to bicycle paint, but I don't really know anything about bike aerodynamics.

Exactly; this is just what I couldn't be bothered to type as I was tired last night.