Tough one, Lee. I'm sure that you want the wood to all look the same but it is very difficult to get different kinds of wood to all look the same. There are tone sprays that you can use on furniture but this would be very tough to do on a staircase. My best guess, and it doesn't help not being able to see it, is a gel stain. These are more opaque and the wood grain will not show through as much, but you should be able to get less color variation between the different woods.
Good luck and let us know what you did and how it turned out. Henry in MI