If you have been given the guilty verdict, then you have been proven guilty. Subsequent DNA testing in this instance would be to exonerate this verdict. So innocent until proven guilty, then once proven guilty, it becomes guilty until proven innocent via appeal.

To your second point, if you classify the literal possession of the stolen items from the burglary as a suspicious coincidence, I'm not really sure what you actually consider evidence? This is pretty much the smoking gun here, we even have testimony that he sold the stolen laptop so it's not like they just magically appeared in his car without his knowledge...

I do find it strange the county prosecutors are pushing back though, but that's where it ends really.