I can confirm the textures do work on 4.9 with Metal.
Yes that happened to one of my materials, easy fix.
Do you know anything about the stationary lighting being built incorrectly? - The bounce lighting is built correctly, but there is no direct sun light and shadows. Enabling/disabling area shadows doesn’t change this outcome and this is happening to mobile and desktop lighting.
In the mobile preview, modular shadows do not appear either, I tried my character and movable static meshes.