You have only 2 best Zelda games, A link to the past(SNES) & Ocarina of time(N64), not to mention on Majora's Mask(N64), i still love it personally.
It's kinda weird, a lot of Zelda fanbase 100% suggested Ocarina of time while the rest communities wanted Majora's Mask remake so bad, i have no idea what's wrong with those people.
Oh yeah, #4 your question: Are the Zelda games really so long?. The answer is, it depends on your gamestyle, some people finished the game just main quest usually 3-8 hours then turn off console without doing sides & some of them took a while doing side quests & explore secrets to complete, i don't know how long it takes but still depends. Wind Waker is only i completed 100% everything... I think took me a month lol, the rest of them i finished just main quest because i'm too lazy. 
Advice: Do not watch let's players walkthrough on youtube.
