Joe, I got the feedback by now. Sorry if it's in brasilian, but my friend only speaks that language. Here it is the conversation:
I asked him if there was any error related to mixing the seeds, and that was the answer:
"Impossível qualquer mistura de sementes. Resta saber se quem recebeu mais de uma qualidade nao as misturou ao semear. O que acho improvável, visto que vão embaladas e denominadas. Como vc mesmo as recebeu."
So that seems it's not the cause, nor mixing of your seeds since they were all labeled and, to be sincere, this guy never gave me wrong, false or mixed seeds in more than 5 years. Furthermore, he added:
"Mas de imediato posso dizer duas possibilidades. Polinização cruzada ou sexualidade. Como tenho certeza da procedência das sementes vale um estudo mais profundo. Para isso tenho os departamentos das universidades para uma analise mais científica."
So it could be that there has been for strange reason a crossed pollination between varieties! Very rare, but it also happened in the past to him. He owns one of the biggest farm in Cerrado with a lot of fruits cultivars. So it could be..
When I asked to him why some seeds were with different colours of the same specie, that's was the answer:
"Sim, coloração é normal. Todas, inclusive marolo tem essas variações. Dependem do ponto de maturação do fruto, da secagem, do tratamento e outras variáveis m Marolo por exemplo tem infinitas colorações . Desde a casca do fruto, polpa e sementes. Mesmo sendo da mesma matroz vemos variações"
Until the seedlings are more bigger and the leaves are in their right shape and consistency I think is difficult to say they are not A.coriacea. But the fruit is the truth: I will ask him to contact his friends in university to have a feedback from them as well. If the answer is not satifying you I can arrange your payback to what you received. By my side, I will keep mine since they could be a very rare variety I wouldn't miss.
The nature is very strange sometimes!
hope it clears for the moment,
Giampaolo