Well, first, as I'd noted, I tried to match this up with canon ArM.
Of course, TSE made some big mistakes, such as separating Veneto and Istriot so much, but I did consider this paragraph about Veneto and other languages. My placement is consistent with this, while your placement goes the opposite way.
I let ezzelino guide my hand on the languages around Italy. This is the main post from ezzelino, but ezzelino and Xavi made others about Veneto.
However, different linguists classify things different ways. So in choosing between the ways, I decided to favor what I got from that canon paragraph plus what ezzelino and Xavi said.
Also, I neither speak nor read any Italian, so everything in Italian has to go through Google Translate and hope for the best.