One of the things your wife needs to weigh Cyn is quality of life.
If your kitty is running around and enjoying her life for the most part, then i think trying the pills would work.
The other two methods of treatment seem too invasive, and indeed she is too old to even risk putting her under anaesthetic for the surgery.
If she takes pills without too much of a fight, i would personally suggest that method. and if she were my kitty, that is what i could choose.
IF at some point, taking the pill becomes a huge daily battle, then i would let your kitty live out her days in peace and forgo the treatments.
I think what it comes down to (and this has applied to my pets too), i do everything nessasary medically to keep them going when they get older, but when the treatments start to outweigh quality of life, that is when you'll know it's time.
Animals are special creatures, they will let you know when it's time for them to go. You'll know right away. But if your kitty is in good spirits and enjoying her life as you described, i think that pills would be the way to go for now!
Sweetpea