Ft & remix ? What does it mean ? (in music)

Ft in music I usually see like : Fat Joe Ft Akon or Flo Rida ft. T.Pain
I think Ft stands for featuring. However, I don't know the exact meaning of it. When i look it up in a dictionary, it give an example for this word : sb featuring sb...

Take the 1st example above, Fat Joe Ft. Akon, so who is the main singer, performer in that song ?
And another word I don't know is "remix". How does it work ?

Thanks so much,
I look forward to your replies.