Steel wheel, SBP

Hi.
Yep they are disc on the front These are factory, but a slight cheat in that the calipers are later model. - see pic below from when I replaced the discs and rebuilt the calipers a few months ago.
Don't have a pic of the outside of the drum but I'll get one later (this evening I hope).... suspect they will be the same as a US drum.

The pic below is the standard Aussie wheel mounted on the rear, I could run this lottery ticket that was folded double around the entire thing, so I suppose the bolts are holding the wheel very central in this case.

From just what I can see the rotor assembly looks just like mine. I have a feeling it is the way the aftermarket wheels are made with a one fits most concept stamping using different dies before the stud holes are drilled. Your factory wheel has four nubs to hold on the small wheel cover and the aftermarket only has three, is that correct?

I really don't see a problem with the way the wheel is centered. In your first group of pictures you only have one lug nut installed and the wheel is resting on the studs so it makes it look worse than it really is. Looks like a pretty decent fit on the disc hub.