Questions concerning amount of lines, and potential stats

I have a few questions.

1. What determines how many lines an item is allowed to have?
2. Can all levels of items, from 1-200, get 3 lines? Or must a piece of gear be a certain level to get 2 or 3 lines?
3. Since miracle cubes cannot change how many lines an item was allotted, is there any other way to increase the amount of lines an item has outside of premium cubes?

I need to know these things so I can find out if the new eternal/immortal rings and the warrior-only dragon ring can get 3 lines of potential.

Thank you for the help!

1. All items can have 3 lines. All items can have 2 lines. Its random.
2. See 1.
3. Nope. Only premium cubes can change number of lines.