My partner and I were shocked when we received our first "quarterly" bill as we only had a 10% maintenance allocation and this bill exceeded that by almost 3X, totaling to $1985 and that absolutely killed our cash flow for the first 3 months.

I would use over 3x your allocation.  

So his cash flow when allocating for all expenses is negative.  

I don't think the thread is dealing with the issue of whether or not someone is married but with how do you allocate income when multiple unrelated people are wanting to live in a property?

There is maintenance/cap ex, vacancy, property management (even if doing it yourself it is a job and should have expense allocated), and miscellaneous. 

It could be a simple contract that outlines what each person brings to the table (the homeowners agree to the future sale of the property and all sides agree on the allocation of the sales proceeds).

I would lobby for expensing this if it was my return.Charles...I thought the concept of depreciation was to allocate expenses to the year they produce income and not to "exhaust" the use of the property.

Your accountant does not know how to file a partnership return.The great thing about partnerships is that you can dictate how allocations get split without considering of capital contributions.The only consideration to factor in is that if you do not have any capital contributions, your basis would be $0 and would be limited in taking losses on your individual return based on 'basis-limitation' but that won't impact the filing of the partnership return the way that you are discussing.

Can you sell or allocate this to yourself or other people, the upfront additional write-off per your agreement.

It sounds like your parents provided you a loan and do not own the property.The gain will be allocated to the person who owns the property(The one on title).