You have to complete the thieves guild missions including vex's and delvins additional jobs, then go and find brinjolf and ask him about becoming the guild leader
The items of clothing from the thieves guild is the armour you get from them when you become a full member of the guild
The only armour that is close to the thieves guild is the actual thieves guild armour which you get when you become a full member of the guild or there is the nightingale armour which you get when you become a nightingale priest
Yes, you can.
Skyrim for Pimps - 2011 The Thieves Guild 5-9 was released on: USA: 14 August 2013
Yes, you become a Nightingale close to the end of the Thieves Guild questline.
Mercer Frey, the leader of the thieves guild in Skyrim, is voiced by an actor called Stephen Russell. He also provided the voice for another thief, Garrett, in a different game titled "Thief".
They are used for when you do side quest for one of the Thieves guild member.
You can't but you can get the Skeleton Key as part of Thieves Guild quests which is a unbreakable lockpick!
The voice actor that played Captian Price also plays the Character of Delvin Mallory from the Thieves Guild in Skyrim
48 hours is the time when you are out of the vicinity of the chest.
Well if you are referring to the armor I know it just powers up your current thieves guild armor (one piece of it) to make it stronger. If you are talking about the trainers they have in the thieves' guild I know there is archery, lock-picking, and sneak. I am also pretty sure they have pick-pocketing and light armor.
You need to join the Thieves guild, and talk to their members.