Nice idea, however my quick thoughts are.....
I am not sure about how much need there is for extra heating in Matera? This stove design is probably a bit excessive for just the cooking requirements of one household. A big part of the design is that the gases given out from the wood as it is turned to biochar are burnt, which reduces pollution + produces extra heat energy which is put to good use rather than being wasted (as is the case with the way a lot of biochar is produced)
I am also hoping to have a prototype built and operational long before the unMo residencies start.
I have also been getting the feeling that I've recently been spreading myself a bit thin, involved with lots of projects, but with slow progress in all of them.
Working towards an unPilgrimage to Matera, although a very nice idea in many, many ways, will take my energies from other things and for a while now I've been feeling the need to focus myself a bit more to make significant progress with existing projects.
I will however give it some more thought (maybe a different design for Matera?) and have a look at the unMo residency documentation.
I definitely think that there is lots of room for value adding with the farmers. My preferred route would probably involve large diversification of crops and shifting to direct involvement with end users of the crops - some kind of community supported agriculture quite possibly with crop processing tied in somehow.