Well, as has been discussed in another thread I started, the implication seems to be that Perfect Susanoo is an EMS technique at best, not a Rinnegan one, so perhaps Izuna had some form of it.How do you figure those are Madara's techs when he has Izunas eyes? the techs reside in the eyes not the body.
So far we haven't actually seen Madara use Ameratsu, so he may have an additional power as yet unseen instead (maybe winding time backwards or something?). Maybe Izuna's powers were somewhat different to Madara's also. We shall have to wait and see.