Front door could be different than the rest of the doors.

Here is what I found in my research. Based on that I went with solid hardwood floors. First off the reason why people say engineered floors look not real, even though the top layer is actual wood is because most of them are constructed with rotary peel veneers. Expensive ones may give sawn veneers and those will look like hardwood. Google search this and you will see what I mean. This is the reason the engineered wood just don't give you the variation and depth that hardwood can give you. With hardwood you are actually getting cross sections of the actual log not a peel of the log. Engineered layer on the top is wood like peel of a log like how you peel a potato It is a complete different wood grain look. So if you ever wonder why engineered wood look laminate like or plywood like then that is because it is constructed as such. Engineered has its pros of being more stable to temperature change and is easier to install but for a discerning person with a keen eye may want the actual warmth and variation of real wood will always lean to hardwood. The engineered wood industry has taken off in recent years providing fancy wide plank , hand scrapped, distressed and various other looks but almost none of them will provide you boards over 4 feet long and all of them will have the notorious beveled edge. What's the use of 7 inch wide planks with 48inch max length. In my mind it does not give you the solid plank look that century old houses had. I am in the middle of installation and I will post pictures when complete.

I would have a look at refinishing the old oak instead of removing. The oak is probably an orangy colour which is not the real colour of the wood, it is the colour of the "finish". Old-time finishes (and many still used today) turn orange (called "ambering"). If you remove the old finish you will be left with a very light (almost white-blond) oak (assuming this is white oak and not red oak). A clear coat finish (non-yellowing polyurethane) will leave the old oak in the "white-blond" state. This would be as close to a "light wood" floor as you can get without removing and replacing. Because you have a very limited amount of space where these two floors are "visible" at the same time, I would say go for what you want. A Maple wood floor is easy enough to reproduce at a later date. Be aware that maple yellows ALL BY ITSELF!!! That beautiful, pale blond is gone inside of a year...may be less. The end colour for maple = "margarine yellow". Beech or Birch will stay true to colour better than maple. Maple turns very yellow...and it has nothing to do with the finish (an ambering finish can make it worse...).

That cherry stain is VERY strong! If you get a tone clash (like walnut brown up against PURPLE cherry...just as you have planned) you are going to have the Clash of the Titans in your home (and yes...I'm referring to the REALLY bad 80's movie...). It won't be pretty. And then to add insult to injury, you are about to attempt to get gray to "play nice" with a purple/cherry stain......ooooohhhhh no. Of course this is your home and the decision is yours. You can do "what you want" - but realize that it would take an INSANELY TALENTED Interior Designer (paid oodles of money) to get these three things to work. It will be hard enough to get the woods to work (I shudder at the clash of tones...not even "undertones"...this is a full-on TONAL clash)...you add in a gray paint and this is going to be VERY hard to work with. For me I say, Paint the risers white. Paint the spindles the same white. Stain or paint the treads a SUPER dark colour...almost black. Paint the banister the same DARK colour as treads.