I think looking through the interactions and seeing if there's a pattern is a good idea, and I agree that it's difficult to know what might be going on in his mind. I know my H is a closed book- I can never tell what he's thinking, so it's better for me if I don't bother!
In terms of the phone call, could you just call to say hello and see how he is? I don't think you need an excuse- sometimes just saying hello is a nice thing to do. I'm not against having topics to discuss prepared though! In general it's seemed to be as though actual conversations rather than mail/text has been more effective for you.
I also wanted to clarify what I meant about option 2 being my gut feeling. I was thinking that since you told B when you guys ended things that you'd call him when you were ready he might not be aware of what your feelings are towards him. From that point of view, I'd see saying something about your feelings as planting a seed of thought in his mind that things aren't closed; do you think he knows it's not over for you? Whatever his immediate response would be, anyway, I wouldn't see it as the end if he said no; I'd see the point as getting him to think of you in an R way subconsciously, which would make it easier if he did say no. And if he reacs angrily, all the better- then you know you're REALLY affecting him and have a good chance. I wish my H would get angry with me sometimes!
