Those would explain your first problem. Indiglo gauges generally have a separate switch (When I have installed them in other peoples car, I usually trigger them with a relay) because they have different wattage draw than your dash lights have. It was originally my understanding that your dash lights started working after you replaced your headlight switch, so I didn't bother asking.
There is a very good possibility the headlight switch you used for a replacement is bad if that is the case, but to be sure, make sure that you are no longer getting power to the tail lights when you turn on your headlights.