Actually Nathan, this was exactly the kind of reply I was looking for. I guess my rephrasing worked better than you give me credit for! ;-)
In all seriousness, this kind of careful thinking about portfolios and pathways to deep decarbonization is the conversation to have. I think you've presented some great hypotheses here. I'm actively involved in research testing several of these pathways using power systems modeling approaches at MIT, and I think you present valid hypotheses. They aren't yet proven, but are credible (and not too different from my own).
I personally hypothesize that we could see a somewhat higher share of renewables and nuclear together, if (a) renewable costs are lower than nuclear and (b) nuclear can operate as flexibly as most modern reactors are designed for (and/or c, we have some additional sources of zero-carbon system flexibility, such as storage, demand response, or power sinks like power to gas). In that case, wind and solar will penetrate until they have destroyed their own economic case (i.e. the marginal cost equals the margina revenue of adding additional units of wind) through price supression and possibly curtailment. Then nuclear will fill the rest of the low-carbon energy needed. But I think in this case we will see larger shares of renewables than you hypothesize (more like wind and solar shares close to their capacity factors, so in the Texas system I'm modeling, about 30% wind and 18% solar).
If nuclear is cheaper from the outset, then wind and solar penetration would be marginal, unless nuclear penetration is constrained by non-economic factors (i.e. political opposition).
Stay tuned for some more concrete findings soon...
In the meantime, THIS is the conversation we should be having in my strong opinion. Thanks for the comments.