A few questions. Looking for some help.

I have several questions. If anyone can give an answer on any of them it would be appreciated. So I got Destiny as a bundle pack when I bought my ps4 (the white one) almost a year ago. I've been a pretty avid COD player for the past several years. I liked Destiny pretty good but was not any good at the PvP at all. Too different from what I was used to I guess, so I stayed away from it and just played the quest. I finished the game so I was pretty much done with it for then, so that's about the time I picked up Advanced Warfare. After that I didn't touch Destiny at all. After playing the hell out of AW I finally got bored of it. So about a month ago I just figured I'd play a little Destiny. Since I last played The Dark Below and House of Wolves were added. I bought the expansion, and I've been playing nonstop ever since. I even started getting into the PvP. Since I started playing again I've realized that this game is way better than I had thought before, and I'm really into it.

So here's where I get to my questions. There are several parts of the game where I feel like I am way behind the curve, especially now after downloading The Taken King.

1. I don't have my third subclass. I am a warlock now at level 38. I thought I saw that the third subclass is available at level 25. Do I need to have both of my other classes completed? Voidwalker is complete, but I still have a little to do on Sunsinger.

2. What happened to Crota's Bane Reputation and Queen's Wrath Reputation bounties? After the update last week the bounties are gone. How do I build my reputation with them?

3. It says that I can earn legendary marks by dismantling legendary gear. But when I dismantled one of my legendary weapons, I didn't get any. What's the deal with that?

4. When I was playing the game in the beginning I was more just a casual player. I didn't realize how much completing bounties was important, so I didn't do them much. Hence I don't have much Vanguard or Crucible reputation built up. Also I never joined Future War Cult or Dead Orbit or the others(didn't really understand that part), so I have no reputation built up with any of them. This is where I feel like I am really behind in this game, since I am not able yet to get any of their gear yet. My question here is, would I be better off making a new character and starting the game over so I can build all of that up as I go along?

Sorry this turned out so long. Thanks in advance for any help. See you out on the battlefields guardians!