Some of the characters are tough to rank.
The difficult decisions are Gohan or 17, Piccolo or Buu (with 18 possibly belonging in this discussion - we have very little information on her strength), and Roshi or Tien.
Gohan and 17 both fought (briefly, in Gohan's case) against SSB Goku, and both seemed to be on similar ground - they each held their own, but likely would have lost had the fights not been cut short. We won't be able to sort these two out until we see them in action.
Where does Buu rank? He handled base Goku with relative ease, so there's that. Is he still weaker than the Super Buu that got thrashed by Mystic Gohan? If so, then he can't be stronger than Gohan or 17, but he's probably ahead of Piccolo, who couldn't put any damage on base Goku with his explosion. This is a flimsy argument, but it's all we have.
18 appears stronger than Krillin, but that's all we know. Could she handle Piccolo or Buu?
If Roshi's was using his own power when under Yurin's influence, then Tien is the weakest character on the team. Either way, these two appear to be a good deal weaker than anybody else.
That's the best I could do.