In the spring of 2012, I attempted to graft a Pear scion onto my apple tree using Winter Banana Apple as an inter stem. (All of he grafting i do is "Whip and Tongue" grafts wrapped in grafting tape. I then coat the wrapped union with grafting wax) The parent branch was a Winesap Apple branch with a grafted Winter Banana Apple scion from a few years before. (I actually have two of these paired branches.) I then attempted to graft two "Kieffer" Pear scions onto my two Winter Banana Apple inter stems. The "Kieffer" Pear scions started to grow, but died a few weeks later. This spring (2014) I attempted to graft this Apple / Pear union again using the same Winter Banana Apple inter stems. I had just enough branch on my Winter Banana branches to try this experiment one more time. This time around, I used "Sunrise Pear" scionwood. The grafting was a screaming success! (I had enough "Sunrise Pear" scionwood to graft two branches onto my apple tree, and two more onto an ornamental pear. All four pear grafts were a success!) I have no idea why this experiment failed in 2012 and was a success in 2014. I do not know if it had to do with the pear variety used, or if it had to do with environmental circumstances. I will re-post in 2015 with an update. There are a few different treads on this subject so I will be re-posting on those threats also. Below are pictures taken on 07/27/2014.

A little alarm is going off for me on this one. Had you said quince I'd say it was worth a try, but I think hawthorne won't work. Still, why not try? Perhaps with the right interstem ... ? Joe Real used to come up with some remarkable multi-species grafts, if you can find any of his old posts. Been a few years, though, and the search engine here can be frustrating. Scott Smith has seen delayed rejection sometimes, so it can be a long time before you know for sure. He might be able to tell you for sure. I'd be interested in hearing the results if you give it a try. I did stick a prune onto Nanking cherry a few years ago, and it's still around. But that's a pretty close relationship, and I don't know if hawthorne is close enough to apples and pears, although apparently it is (to my surprise) a pome, albeit a single-seeded one.

I know they graft European pears onto quince, because that is what my Bosc is clearly grafted on. Definitely quince foliage from the persistent suckers that emerge at or near ground level. I would think Asian pear would work as well on quince. I was never very successful getting a decent crop of quinces until last year and especially this year when I found out about the Triazicide Once and Done from this forum. I grew nearly perfect, worm free quinces this year. A couple of coddling moths in a handful of the cores, but just a few, but, I slacked off spraying after about late July. Had I done just one early-mid-August spray, they probably would have been pristine. Not complaining, I got way too many as it was.

Some varieties are just more vigorous than others.