Now, the question you need to ask is whether the tax treatment you propose is valid.  

I'm interested in buying a property and want to propose seller financing.  

So I proposed an Idea to her, the next set of apartments that I find that we should go into partners.  

Which by the way, she is in your age range as well and has the same aspirations, I recommend you touch base with her, you guys can become accountabilibuddies (also trademark pending)🤑I believe the real estate industry is one industry that truly needs to go back to the tradesman/apprentist system.My recommendation would be to do exactly what you are proposing to do, seek out a veteran investor in your area, (Not a guru) offer your services as a birddog, assistant, partner on deals, etc.

To make a proposal more attractive to a flipper, offer not to take your wholesale fee up front but to take it upon a sale.

You can buy from builders and sell to retail buyers.What you are talking about is building on a developed lot and then selling to a retail buyer.What you are proposing could be referred to as putting all your eggs in one basket.  

I'm currently working a refi with them now they're proposing a 30 year fixed rate product for bundled single-family homes.

A lawyer licensed in your jurisdiction* will need to review any proposed contracts for legal sufficiency.

There is a few big development plans proposed for this neighborhood (condo and townhomes project proposed just 1 house away from this property).

I can tell you that I have done exactly what you are proposing and have had no issues in 10 years, but you should be going in with your eyes open and understand the consequences.