Honestly, the less actual interaction and decision making you try to get from people, the smoother it'll run. Trying to get input from Spam every few minutes of play is just a bad idea.

Knowing Spore, I would suggest you just set up a few questions for people to answer to decide how you play the game. Ask what route they want you to take in each stage, the peaceful/middle/hostile thing for each one, and let that be it. Then once they've decided they want you to be a murder machine forever (knowing Spam, it's very very likely), you can play through and name each new species (probably best to only do the ones that have major changes) after a person in Spam. Once you hit the civilization stage you can also name buildings and vehicles after people.

So basically after the initial setup, you can just do an after action report style thing. No need for people to be actively involved, and you can do whatever you think will be amusing for the creature creation and naming and things. I would highly recommend making a big floppy dick creature and naming it the Smiral, for starters, although you'd have to censor the images of the creature to not get in trouble with the mods. :hehe