Nope. Once it's bottled, whiskey (or any spirit for that matter) does not age or get stronger. If the bottle is opened however, the flavor can change over time. I believe it's due to oxidation. I've never had a bottle of liquor long enough to taste any change though Welcome to the site btw!
Hmm, possibly. I know I found this open bottle of old Remy Martin a few years ago in my parents liquor cabinet, from like the early 90's. That stuff was un-f***ing-drinkable. It was totally the most vile thing of all time.
Once whiskey is bottled, it won't do anything to gain flavour from its bottle. All of the flavouring comes from the cask. Theoretically, if you open it, it will go bad after a long time but I've never opened a bottle of whiskey and not finished it in a few weeks. Light and heat will also cause it to go bad. You can refrigerate wine and some whiskeys but scotch whisky (yes it's spelled without an "e") should be left in a cool dry place such as a pantry.
After bottling, the liquor no longer gains flavour, no matter how long you leave it there. That goes for any alcoholic beverage. Whiskeys and wine gain their flavour from the cask. If you open the bottle however, it will go bad after a long time. Beer has a very limited shelf life. I only drink beer at bars or right after I buy it from the dep (yes, in Montreal, they sell beer in convenience stores, called depanneurs in French)
As for wine, I've heard that the wine buried with the ancient Egyptian pharoah's are nothing more than vinegar now. You're supposed to flip it around every decade or so.