One of the first articles I read after an MRI confirmed the diagnosis of an AN, was a paper from Harvard med school that stated there were two major factors affecting outcome from AN surgery. They were tumor size and the experience of the surgeon. As almost everything you read here will tell you, experienced surgeons are the key because no one can control the tumor size on diagnosis.
In my case I discussed with my surgeon having a subtotal removal of the tumor if the surgeon found any difficulty dissecting it from my facial nerve. I told him I'd prefer to risk regrowth of the remaining tumor than risk facial nerve function. I did have a subtotal removal, the surgeon removed 95% to 97% of the tumor except for a sliver on the brain stem and the rest on the facial nerve near the IAC.
As far as radiation, the major treatment centers for radiosurgery like UPMC (GK) and Stanford (CK) have excellent records for facial nerve preservation. Data are available on their websites, if radiation is possible in your wife's case. Douglas Kondziolka is a GK specialist now at NYU med center, he was a practitioner at UPMC with Dr Lundsford.
In some cases, complications from surgery or radiation are inevitable. When complications arise they are most often temporary, and when not temporary steps can be taken medically to correct them. And some complications we just get used to and they become less bothersome.
In my case, I did have a mild face droop that lasted 10 days. I had vocal cord paralysis and paresis that gradually improved for over a year and are now gone. I could not swallow on the right side for a year, but that has improved almost completely. The facial numbness I had before surgery remains but I am used to it by now. I list these issues to illustrate that complications may resolve quickly, or more slowly, or even not all. I am also SSD and have adjusted well to deafness.
Your wife will, in all likelihood, have a successful outcome. Any complications will likely be temporary, and for any that are not, she will adjust as we all do.