Regarding who to invite and who not to invite I answered my own question while discussing with my Mother.

Will this person's attendance "make my day"?
will I even notice if this person(s) shows up?
If this person doesn't come, would it upset me?
I have 83 cousins- & an entire "Step family" I can't possibly invite them all. I had to draw the line somewhere and the answers to these questions helped my cut down my list.
Hope it helps.