Even though you want to invite as many people to submit a tribute as possible and as many people to attend your party as possible, you don't want to invite any jerks.
What do I mean by a jerk?
- Negative Debbie Downers who find what's wrong with everything.
- Egomaniacs that must be the center of attention, regardless of what the circumstances are.
- Selfish people that will keep interrupting the reading for their own needs.
- Impatient people who will become easily bored and start distracting the group.
Well, you get the idea. You won't know if many of the people you are considering inviting are such jerks that they'll spoil the experience. If you're not sure go ahead and invite them and give them the benefit of the doubt.
Most people will pay attention and ask about what's meant by some of the contributions and spontaneously remember things about the special guest and bring them up. That's all great, and should be welcome. If anyone gets the discussion too far off track, you'll want to interrupt and ask the guest of honor to go back to reading the tributes because you don't want to run out of time.