Is it the last transfer or do they plan another one?
ANAS website doesn't explicitly say, but there are reasons to believe this will be the last one.
For instance, 15 out of 20 regions (11 + 4) have been addressed. The remaining 5 regions are the so-called "special status" ones (Aosta valley, Sicily, Sardinia, Friuli-Venezia Giulia and Trentino-Alto Adige) which have different rules in their relation with the central State. For instance, the 2001 law that devolved those ANAS roads to the regions did not involve special status regions in the first place.
EDIT: Actually, my previous statement is false.
Roads in Tuscany have been transferred back to ANAS in both occasions, so the regions addressed are 14. Veneto is the only "normal status" one that wasn't addressed.
So apparently regions can be managed in rounds, meaning that there is no way to know if there will be more instances also for regions already addressed.