First of all...relax. Think of it as a group of friends getting together to share something you all enjoy. It sounds like you're putting extra pressure on yourself by calling it an official "crop" and trying to make it perfect.
I really think you have a great start already. Friends. A plan to do some kind of challenge. (I like that idea!) Maybe until the group is able to buy "group" toys with your combined money, you can coordinate certain people to bring certain tools so you don't have a lot of people bringing duplicates when they don't need to. k
And don't forget food. Preferably including some kind of chocolate.