What? You are assuming too many things about the Anderfels.
Actually, it's stated in World of Thedas and other sources too that the Anderfels is without a doubt the most pious of the Thedosian nations and firm believers of the Chantry (the Orlesian one). There's a king ruling in Hossberg, the capital, and he uses religion to strengthen the authority of his royal tribunals. In fact, when the king decides to murder someone is called "absolution", not "assassination". The influence of religion is prevalent everywhere in the Anderfels, completely opposite to being "independent from white and imperial chantry both".
However, because of the darkspawn, royal authority is only felt strongly in the capital. In the remote villages, Grey Wardens are the only ones defending them, so it's true that they hold a lot of power. However, the standing army? Not by far. There are a thousand Wardens present in the Anderfels, the largest number in any Thedosian country, yet inferior in numbers to a large feudal lord's army.
Fenris is the only CITY elf we have talked about magic in some depth. Dalish, of course, have a different point of view, but it's an important matter since Dalish are inferior in number to the City Elves. Fenris is a good example to break preconceptions because it proves that the People (as Lob would say) aren't a monolithic group and that magic can be considered dangerous by elves too. If Fenris' opinions are in the majority or the minority is something we don't know yet. As you said, after all, absence of evidence doesn't mean evidence of absence.
But still the country survives because of grey wardens. They are much more important that useless army that keeps kittens of capital safe. The fact that Anderfels is the only place grey wardens can recruit as many mages as they want speaks volumes. The chantry usually doesn't allow excess number of mage grey wardens to exist at a time but its powerless to do anything in Anderfels. How else do you explain all the mages in Warden keeps of Anderfels?
Except Fenris had loss of memory several times and he is Templar version of Anders and just like many people don't care what Anders thinks, many feel the same about Fenris. He is a hypocrite who would sell everything to become a mage himself "to hold as much as power as Magisters" ~Fenris drools. try rivaling Fenris once a while to see his true face, friend fenris is just having a good time because Hawke supports him.