The one missing piece here seems to be how each individual human's morality blob corresponds to any other's morality blob. I suppose we could argue that the CEV of all humans would be the same (certainly my own CEV would want happiness etc for people I will never meet or have knowledge of), but you didn't actually say that and if you meant it you should say it. Is this covered in an interpersonal morality post elsewhere?

I spent much time searching for the morality outside myself once I lost faith, although I assumed it would hold true to most of my assumptions rather than be something scarily different. the best I could find was Kant's categorical imperative since it claimed to make good logical, though I found it to be flawed as conventionally interpreted (although I suppose it may be as good a source as any of rules to follow in general).

That morality is extremely complicated and not reducible to a few simple rules does make sense to me upon reflection, however difficult it makes it to argue with religious people to whom 'The bible has guidelines, but the real specific answer is complicated' is not an acceptable answer -- but that's their problem, not a problem with the truth.