CuriousJa- since you're doing your "jem", I doubt it's in really dirty shape. So I'd say skip the Dawn and just use a strong solution of regular wash soap.
I'd put a layer of SG between the AIO and the
Souveran, myself. I DO NOT get streaking/smearing or anything like that when topping SG with a carnauba. Put the SG on VERY thin (so thin you can barely see it). Let it cure as long as you can before buffing it off (even overnight). Fog the surface with your breath when buffing it off and use a good quality MF. If you want to REALLY play it safe, after buffing off the SG, wait at least 24 hours before topping with Souveran. It might sound lke a hassle, but the extra protection of the SG is worth it, IMO.