Hi - I'm sorry for not updating this thread.
NCLSEA - long story short, no. LocAuto were an absolute mess picking up in late August, and when I called back on Sep 1 to try to apply free days to the remainder of my booking, I was told that the prior rep had been severely misinformed. Thereafter followed over two dozen email and phone exchanges, which I will summarize below.
National *will* allow you to redeem free days as of mid-September in the UK, Ireland, France, and Germany. This is, of course, in addition to the old list of Canada, Aruba, Belize, the Cayman Islands, Costa Rica, Curacao, Guatemala, Mexico, Peru, Tortola, and Trinidad & Tobago.
The caveat here is that you must call National to book for you across into Enterprise's system, and they don't have full visibility to local inventory. I was in München in late September, was told by National that they had no cars (and would not for a week), picked up a Hertz vehicle, and happened to stop by the Enterprise counter on my way to pick up my Hertz rental. The manager looked shocked and said he could put me into a car right there (I ended up going back the next day and got a Jag XF from him). National customer service subsequently confirmed via email that their phone agents do not have all inventory visibility to Enterprise's stations.
Now - going back to LocAuto in Italy. If Rome is any indicator (and I am a fluent Italian speaker) - do not expect to be treated the way you would at any other National location. Extra drivers are charged at 50EUR per day - elite status doesn't matter, nor does any corporate rate code. There is no computer connection - you will and must stand in line before they take your license information and a carbon paper imprint of your credit card. They pulled a massive bait-and-switch with the car level I reserved, but that car thankfully had a mechanical fault the first day of rental and after arguing they gave me a much improved replacement vehicle.
Good luck. Hope this helped.