<p>Is there a library/software which can accept a number of keypoints and matches of them between images and produce a morph? Or any ideas/algorithms on how to do it?</p>

An older piece of software by
Gryphon Software
could do image morphing. I saw an article about it from 1994. I couldn't find a company site, so they may be abandon ware now.
Her is a quote from a Wikipedia article about a film editing
technique called Dissolve
.
In non-linear video editing, a dissolve is done in software, by interpolating gradually between the RGB values of each pixel of the image.
Hope that helps.