Raise from who? If you mean raise from the outside world all 4 of you are going to have to pour love, sweat and tears in before the outside world is going to even look at you. If you don't take the risk upfront, no one else will. Until you have, at a bare minimum, proof of concept your valuation is irrelevant. The upside is you have other sources of incomes to survive in the interim.

As for the % division in partnership - easily sorted by how much energy/time you're each going to put into it. Did someone start the concept or you all did together?

As for capital - put as little in as you can UNTIL you have a valid concept that's been market tested