Some excellent advise so far to some very well thought out questions
1. All waters that have oxygen, food, structure and cool temps can
hold fish. Something most novices overlook (and many veterans for that matter) is observation. Dont just wade out and start casting. Spend some time looking around, turning over stones and looking thru vegatation to see what and if theres a food source. If theres bugs in the air, spend some time watching for a rise or other clues there may be fish. Pay close attention to current breaks, soft riffles, bolder edges, cut banks... likely water.
As a beginner it can be very beneficial to fish areas where there are other fishermen. not only is it a clue theres fish here, but watch them a bit to learn what theyre doing. Just know good fishing etiquette when you fish around others.
2. Yes and no. Fish can certainly survive and grow for many years, but many hatcheries are genetically engineering sterile trout. This is to keep hatchery and wild fish from interbreeding.
3. I dont know for sure, but I believe these states have some excellent trout streams. No such thing as an excellent hatchery trout stream
4. Again, yes and no. Some pay to fish places have very educated trout that are hard and rewarding to catch! Yamsi Ranch comes to mind.
5. The first half of this questions been answered well. The second half is YES! Fishing conditions are constantly changing making most every fishery technical some days, and strangely easy others. Heck it can change like a light switch. But when facing wary, heavily pressured, clear water trout you should always have your A game.
Great questions and welcome!