Depends on how weak you view Future Gohan when compared to what can be argued to be pre-Time Chamber Trunks.
17 & 18 > Gohan
15 < Trunks
There is certainly an argument that Trunks is more powerful than Gohan, but idk if I’m willing to argue it’s enough to make a difference to the battle.
Arguably 17 & 18 could beat Super 13 if you rate Future Gohan to be roughly as powerful as pre-Cell Goku or the version that fought the mime before the heart disease.