@Joe Ebanks Hey Joe, I apologize for the late reply! First, the hallway and closet that you mention have wallpaper than has been painted over. Are you working to totally redo the house? 99% of people will tell you to take the wallpaper down, I agree but I will also tell you that if it's an old house that wallpaper was more than likely put up correctly (sized as they call it) and it WILL NOT come down easily. No amount of chemical, water, scoring....will make it an easy task if it is like many other old houses with old expensive wall paper put up. So, I would plan on it being a chore to deal with. Other wise yes, take it down...skim coat the walls....primer...paint. The bin primer/sealer will work. The sealing aspect of it is incase there were any lifts in the sheetrock paper, it would glue them down.
Second, the wood work....this will not be difficult once you have the technique down pat. So first you will want to find a board somewhere that you can practice with (maybe from a linen closet or something) because the key is the wood you are applying the stain to. I promise I have matched a thousands oil base stains and when one is sampled on white birch then applied to a 80 pine it's totally different. Either way, take down a sample board...clean and degloss it ...give it a light sanding....apply some wood conditioner (helps keep the stain even across the surface) and let it dry for 15 minutes or so. Then apply some "Jacobean" stain....I generally used PPG Olympic stains so if you can get this it you will be a happy camper. I love the "Jacobean" color because it is dark but has a perfect balance of red, black, brown, and yellow....so you will be able to play around with one or two coats to see if it matches closely enough or you will see that it needs some more black colorant, etc. It will take some messing around to get perfect but once you do it is a time consuming but easy /fun project. I sure hope this helps!