On a 5 figure job, I would: on the oak use a fine wire brush w/the grain to open up the pores and clean the sawdust and dirt. Then wash with 50/50 alcohol and water.
On the maple, I'd use steel wool first, then the alcohol/water mix.
Starting with the maple, I'd dye it first then stain it. Sand the dye lightly before staining. After the stain has dried, use the stain again as a toner on the light spots.
The oak should be easier to do after the maple to get a matched color, by dying and staining. I don't have a lot of reference material onhand, but you can do a google to learn all about dyes, thinning and matching the colors.
Really, it's easier to match this super dark color than a lighter color.
I don't know if this will help your situation, but bleach on oak turns the oak black.
I don't know how much staining you've done, but sealing the wood first, imo, is like a cheat. If you have an eye for stain, you can definatley see brush marks, rag marks or whatever you used to to it with. On the other hand, if you figure out how much harder one wood is than the other, the sealer can be mixed at different ratios so both woods are sealed the same. For example, a 4:1 shellac sealer on both woods won't do a damn thing. You'd have to go like 4:1 on the oak and 6:1 on the maple if you want to achieve an even stain.
Either way you go, this isn't an easy job. Find someone who knows how to match dyes. Plain stain will probably disappoint you. On a job of this scope it might pay to do the research and add a new skill to your arsenal.
For even better, expert advice, check out these guys: http://www.woodworkingtalk.com/forumdisplay.php?f=8