Once you add 1118 you're pretty much screwed. That yeast will prevent any other yeast from living in the same environment. So adding any other yeast cakes is a waste of time. Also since it's a champagne yeast it probably won't do very well with maltose or some of the complex malt sugars, meaning you might actually end up with more residual sweetness than if you stayed with just ale yeast.
I'd say you've done everything you can at this point. Maybe dry hop the hell out of it to try to balance the sweetness?