What a fine vision. I'd say if things pan out, you'll be working on this for about ever - job security! <g> Here's my $.02, FWIW.
While I personally doubt many of the plans you consider will ever materialize (I would say that to anybody), they set a direction and talking back and forth a _lot_ and working up "plans" helps discover what each of you presents and feels about the future and your part in it. Don't be afraid of the hard questions - will a partner kill it for one of you; if children are on the horizon, how will medical needs be met; what each of you will contribute; what the exit strategy might be if there are unforeseen insurmountable problems. Details are hard to pin down ahead of time, but talking them over allows discovery, establishes direction and maybe brings up new and different slants. That's all pretty important because misunderstandings and disagreements down the road can sap a
project pretty quick.
The other thing is, DO stuff now. Determine and execute small or even baby steps where you each carry some weight and _do_ it. Insist on moving forward. Don't wait on anything. There are material things to be done now - start actually doing them. As you go you'll begin see how each person develops on _this_ path (as opposed to past history), what your strengths and weaknesses are, how feelings solidify or change. Now is a much better time for that that later when you're waist deep in big buck$. Executing doable but slightly challenging projects now is how you learn about the team.
Oh, and JIC, not to forget, the "partners" (SO's) really have to be there in the thick of it. Right now and always. I doubt seriously whether a world vision like you're considering can succeed w/out the full and active participation of everybody involved.
Lastly, time matters. Face it head on. If _the_ plan isn't working on any reasonable, plausible, schedule, prepare yourself to change it, change your expectations, change your relationships, search in other ways, cast a wider net... Maybe even walk away in order to get and keep moving while your
energy, hopes, health, etc have a head of steam . Many ways to move - marathons, sprints, jogs, walks - and rest stops can be a _very_ good idea, necessary, even. But. To proceed under our own helm, we need, on the whole, to keep moving. Somebody once said God gave us the issue of time, including deadlines, in order to emphatically encourage us to make decisions, act, move. Not everybody is always ready, but the river keeps flowing...
It's great to hear of your startup. Best luck to you all on this really hopeful endeavor!
Rufus