I'd go with Lucas. He showed a lot of character during his first couple of years at the club and has won the majority of the fans over. He strikes me as being a loyal sort of guy who would remain at the club for a long time and that is something you need in your vice-captain as, one day, in the natural order of things, he would become captain.
When the time comes for Stevie to hang his boots up I would hope to see Lucas take over, with either Henderson or Shelvey as vice.
Agree with that.
If Rodgers wants someone a bit more experienced then I'd go with Agger or Reina. But otherwise Lucas.