Great news Seattle... Sounds like you have a recipe here that will only add to more baby steps???
Just a thought, maybe you could go ahead and plan the dinner and tell her that if she would like to go this is what you were thinking of and leave it at that. Just a different twist on "asking for her approval" but I'm not sure this works in your sit. Would it be a 180 for you to go ahead and MAKE the plans as opposed to ASKING for her input? Whichever one looks better would be a good choice.
As for dicussion, from my experience, I have played out what I wanted to say in my head, wrote things down and revisited them numerous times before I discuss things w/WAS so that I am ready and things sound more accurate. I have found it to help me so I am doing it the DB way and not flying off the cuff. It actually worked for me several times during my discussions coz H seemed more interested and shocked at my responses which helped keep the convo going.
One other note, you may want to limit the convo so you don't get barraged w/lots of bad things from W even though she wants to vent; it just is a lot to take in at once and be able to respond appropriately. Maybe you could ask her to limit the convo to some extent (maybe even during the course of it) and then revisit it again next week, 2 wks, etc.. so that you both have time to regroup.
Just some ideas that might help you w/meeting. Take 'em or leave 'em.
As for C, I know you don't have to be reminded but give it time. Maybe after you talk and things soften a bit more, it may be an option down the road. My H finally gave into it 1yr after S even though he wasn't totally convinced about it. I'm not sure it was good but we started to go so keep that in the back of your mind. Maybe it will happen one day.