I will endorse this switch only if you send the unused Duopar to me after installing the Acera. Personally, if Grant Peterson says to do something, I generally do the opposite just on principle. If Jan Heine says to do something, I just ignore it since a few years down the road he will have changed his tune and will likely be endorsing what I had in mind in the first place

Seriously though, Mrs. Daka prefers indexed shifting and her 1970 Super Course mixte is decorated with modern Shimano geartrain. Works fine, looks nauseating on that bike. I would expect an inexpensive Shimano derailleur to come with a hanger, but if not, any Suntour/Shimano/Campagnolo compatible one should work. Leave the Huret hanger with the Duopar, it would be harder to replace.