Hi Billy from California,

The apples will not pollinate any pears. The Asian Chojuro pears and like species types of Asian pears all will work as pollinators for any pear such as Bartlett as long as the flowering periods overlap those of yours in your area. 

The idea of a duplication of a same cultivar grown as a different tree will not improve the chances of pollination because of mechanisms that are in place in the stigma are there to force heterozygous continuation of the species, which are often referred to as outcrossing.

You may find partial or fully selfing individuals in the pear or asian types within their own groups that vary from location to location but still know it isn't the normal order of hetrozygous(ly) conserved species. In such cases the selfed pollen is sufficiently slowed down by these pistillate mechanisms for striking a balance of survival. Think of these cases of exceptions to the rule as allowances for a new future pollinator (ie. a son) so that it (mother-species) won't go extinct. 

I think Chojuro is more capable of selfing than Bartlett because of reading sources I found in Japan that have discovered a sport of Asian pear 'Njisseiki' as a mutational clone that allows for selfing. In turn most of Japanese Asian selections (I think chojuro from this) are selfing due to being selectives from the original Nijisseiki mutation. So at least if you do find cropping in your chojuro being alone at least you know why. And that Bartlett does probably not have that "by chance" selected mutation propagated. 

Just to be clear -the first nijiseiki was purely heterozygous and store bought nijiseiki these days and seeds from that will not be the same homologs as the original.