So we contributed the extra capital as a second mortgage.  

We also both contribute to 401k and a roth IRA, & have 2 investment properties that we bought in December 2019 and October 2020, with 2021 being a big scale up year for us. 

Split profit depending on how much money and work each party contributes. 

I would express yourself and figure out why he's only valuing your contributions at 8%.

I contribute ~$15k and my company matches 8% into my 401k program. 

If you contributed 100% of downpayment and handle everything on your own (also, pay for everything down the road), then you are entitled to 100% of profits and I don't think your parents should even mention this project in their tax returns.

My friend and business partner is able to secure financing, so we would contribute a cash injection and he would be able to get financing for whatever we could not pay with cash. 

The account is designed to provide tax advantages, and participants must follow the same eligibility requirements and contribution limits.

Here is a link to Freddie Mac's guideline on seller's concessions: https://guide.freddiemac.com/a...Here is what I am reading:Freddie Mac will purchase Mortgages that include interested party contributions under the terms of the Purchase Documents and this section.Interested parties include, but are not limited to:BuilderDeveloperSeller of the propertyReal estate agentInterested party contributions may include either financing and/or sales concessions.

This rent goes directly to paying off your mortgage.Now, let's say the left over payment on the mortgage and all other expenses is $2,000/mo.Now you are in the same situation as renting, expect now this monthly payment is contributing to the equity in this $800,000 property that you acquired for $28,0000, not to mention that your tenant is also helping you contribute to this equity as well.