Yes you can mix hardwoods and stains...Cordovan finish on oak is like dark cherry, Looks good in a dining room, living room, den. You need to make sure that it starts and stops at a doorway, or it will as Steve says look like a mistake. I agree with Steve, find a local hardwood flooring installer, sample stains, border treatments, etc. Stay away from the big box stores, they hire the indepenent contractors and then charge you more. As far as cleaning the floor, don't waste your money...use a mixture of 1c. white vinegar, 1qt. warm water, 1tsp. dish soap. Use a slightly damp (Not Wet!) rag go over a small area and then DRY with a terry towel right away!!!!! Continue on the rest of the floor.