On average, yes, but in reality the recession velocity is neither constant nor linear. Points at the distance of the CMB scattering surface are currently receding from us at more than three times the speed of light.

The Milky Way-Andromeda system is bound together by gravity, and so is unaffected by expansion. Newtonian mechanics is all you need to calculate the time until the two galaxies collide (notwithstanding the uncertainty in the current distance and relative velocity of Andromeda).