Different woods do staion differently. Colors can be mixed and cloors be close, however. For instance, the oak might require more dark tones in the final recipe---to approxiate the same stain on the alder. Or if a water based finished is used on one, an oil based finish might be used on the other to darken/amber tone it.

Use a preconditioner on the alder so blotching is minimized---white(Blond) shellac mixed in a one pound cut is best since it does not darken either wood.

Do a lot of testing---for instance when a color recipe is close, I often use the inside of a closet door as the final test---for a look on the real thing.

Thanks for letting me know.

The trim around the door should match the door. I don't work with alder so I am not familiar with how it finishes. Oak is an open grain wood that requires sealing. The grain and pattern of dissimilar woods can result in some strange results. Just my opinion. BTW, thought alder was used a lot to bake salmon.

If you want wood that is stable go for quartersawn oak (also called edge grained) - it is more expensive but also has an interesting flecked grain as well as stability. Alder is nice but I don't think it has the strength of oak or birch for door use. Doors often have objects moved near them which could tend to dent and marr wood. Why not try flatsawn oak for the doors and trim and quartersawn oak for the floors?