Lots of questions, and I honestly have no answers. I don't know what's considered right or not right, and I've learned since we first got that awful call that there's no right or not right in the entire grieving process. Everyone navigates it differently, and we all do whatever we feel we need to do to get through it.
Mind you, you're never really through it, either. It pops back into your head at the most unexpected of times. It irrevocably changes the direction of our lives - sometimes subtly, sometimes more obviously. This isn't in and of itself a negative thing. It just is. Another wave in the ocean of life, if you will, and it's up to us to just ride the thing and see where it takes us.
Maybe after 7 years I should stop fretting over whether I'm doing the "right" thing and just be glad that I'm still here, and still have the capacity, to wonder about these things at all. Maybe "celebrate" needs a new definition, one that extends beyond the narrow-band view of birthday cake and candles, to something a little more reflective of a life well lived. If the day brings me a good memory or two - and it has - then perhaps I should simply close my eyes for a bit and enjoy it for what it is. Everything else is a distraction.