If two individuals own a rental property together as joint tenancy in common with right of survivorship, how would they report the income if they file taxes separately?
For example, assume the property is owned free ...

But you cannot acquire them inside a multi-member LLC filing as a partnership, that is correct.

Communication is one of the most important parts of a partnership.

The tax preparer did our LLC taxes as partnership return with K-1s to both my husband and I. 

If you shop bank to bank you will find different lending options you need to find a bank or lender that offers 30 year fixed rate for an LLC partnership.

Then there's a fourth that will be doing no work, but also putting in ~$25k.Do you guys have any tips for how we can structure this partnership?

The idea is not a hard money approach, but a "partnership" where I am the boots on the ground and the investor finances the process and our LLC holds the properties so everyone has a share in the continued future growth in value of the holdings. 

any innovative strategies always open for partnerships as well so let me know if you’re interested

I am here to hopefully network with like minded individuals and maybe even establish a partnership in the future.

@Heavy Crowns Partnerships can often be a great way to get more done faster, however, I will echo the previous comments and say that you should have legal agreements in place to plan for the unexpected.