How do we best split real estate team assets without a partnership agreement?

In the absence of a written general partnership agreement, California imposes a statutory general partnership agreement on you. All assets belong to the general partnership, but so do all debts (such as reimbursement obligations for costs incurred). Try to work it out with litigation.

I agree with Mr. Doland. You might want to try mediation if you can't reach an agreement with your team members.

I generally agree with my colleagues but, IMO, there is a possibility based solely on the facts you have presented that a partnership was never formed. If so, the creator of the work would be the owner and responsible for the costs associated with creation of the work. I agree this is something you should work out between yourselves so that litigation is not necessary. Good luck.