The question of valuation of each partner's basis is not really a matter of the tax filing itself except that the final computations must be used when filing the Form 1065.
Instead, the information that you have presented as to each partner's contribution, and therefore Partner Ownership Interest, speaks to your need to use a business evaluation that takes in to account the funding amounts provided and the Fair Market Value of the services you provide. In the latter case, you would have to come to an agreement with your partner as to what would those services cost if a 3rd party, at arms-length, were to be paid to provide identical or near identical service.
Some ideas presented by this author: https://www.thetaxadviser.com/issues/2014/oct/case-study-oct2014.html