The OE Ducati fittings are scary money.........£40+ a pair I think. The ones in the above links should work fine. Just try and check they are ok for the pressure that fuel injection uses.
I've not seen an E using QR fittings. I think they are the only ones to do with out??
My '98 BP has adjustable head angle. Again, I think the E is the only one to lose out.
The stepped heads are, indeed as RJ points out, originally for the ST and M's. They went on the E to spread out the production costs I guess. They also use different cam belts.
Don't let the DD boys think they'll fit their 600's