Shroud and hexproof are identical for all intents and purposes as long as you don't run stuff that targets your own creatures. It boils down to a Lord effect vs the Sliver being untouchable to spot removal while Lord of the Unreal is a weak spot in your defenses as long as you don't have a Mirror Entity online.
Speaking of targeting, another Dwarf that could enable Magda would be
Dwarven Bloodboiler. Although RRR is probably too harsh on the mana of the 5C build. However, between Mothdust Changeling and Changeling Outcast, the pump might be a real threat - and it works right out of the box, potentially stealing wins out of nowhere.
A RUG manabase could make the use of BoP more feasible as an accelerant.
As for Ziggurat, keep in mind that it can't be used to cast or activate Pyre (Vial is less of an issue here due to its low cost).