Its been a while since I looked at the hybridization table, but I don't think c. Pubescense will cross with c. chinense...
I might be wrong there... But I don't think so... Definitely something to look into.
You're right, those won't cross. All you can really cross are C fruitsense, C annuum, and C chinense, which are more closely related (might be considered a subgenus, dunno), unless we are talking about a different set or subgenus of capsicum. When you cross interspecifically, you will have reduced pollen production if you succeed. I think c.chinese x c. fruitsense results in 20% pollen production in F1 plants. Don't quote me on that, I'd have to reread the research I read experimenting with hybrids. Some will not cross, produce dead pollen, or produce sterile fruit depending on the parent combination and species being crossed. If you can, I'd keep the cross in the same species. I think you will have to backcross or run into genetic problems with pollen production.