Granted, Goku had to amp himself with the power of the other Z fighters to beat Broly, however, each of them had just been beat to shit by him, thus were tremendously weakened at the time(the Saiyans, for example, couldn't even maintain their SSJ forms, and had regressed to their base-levels--traditionally this only happens when they've literally depleted nearly all of their energy.) That being said, I really don't think they could have possibly lended much to Goku at that point... Yet with their added power, Goku still wtf!spite-stomped Broly.
So I'd have it as: SSJ2 Gohan(Cell-era)~SPCell>Movie 8 SSJ Goku(amped)>LSSJ Broly~PCell>ASSJ Goku. But that's just me. 🙂