1. Those different things you are talking about sound like uv's (Unique Variants) which are given to you randomly when crafting an item. You can buy them from the auction house as well. If you do have ce you can just uv craft which means you craft an item until you get your desired unique variant.

2. Uv's = Unique Variant so they are selling an item which has an unique variant.

3. Well if you want to be a tank I would recommend this armor:

Volcanic Plate set (it has normal and elemental defense, but lowers your attack speed)

Vog Cub Set (Normal elemental attack speed boost)

What I suggest is first find your playing style in the game (Which monsters are hard for you to kill? Which monsters do the most damage to you? Which style of weapons do you like?) and after you answer those questions check out the Wiki (This thread will help: http://wiki.spiralknights.com/List_of_alchemy_paths ) to figure out everything.

4. Leveling works like this:

Items either start at 1* or 2* or 3* or 4* or 5*

So basically:

1* to 3* you can craft straight away without gaining heat (Heat helps you level up your gear max level on an item is 10).

3* to 4* (Your 3* item has to be level 5 or higher)

4* to 5* (Your 4* item has to be level 10 to get make it into 5*)

5* (You have to complete the training to gain certain bonuses of the weapons, armors, shields, etc.)

To obtain a 5* weapon the only one I know of which is direct 5* weapon is the Heater Shield (You just need the recipe mats and heat to craft it).

I hope that helps if it was not clear for you just let me know and I will attempt to help you again.