This is the only app I can find customized for tracking your hours and that of your cleaners, handymen etc...

Nothing wrong with 10% body fat and $300k in the bank.The amount of time and energy that it takes to gain 'ultra-wealthy' status are insane....and you have to give up many things that give you a happy. healthy, well-balanced life.

Private lenders often offer more creative solutions, like interest-only payments or custom timelines, which can be a game-changer if you’re working on a unique project.

I will assume positive intent here that this is not the experience you intend for your customers.

Convince yourself that there's a better than average chance that you will lose, and if you can live with the time, energy and money spent if you do. 

I would have to get with the property manager and mimic the exact plans they have set up in the lease, all of which were probably customized by the PM to get a few extra dollars.  

I don't think I could justify custom cabinets for a $1500 rental. 

Use your energy on something more meaningful.

Expect a custom ADU to take 9–18 months, with 3–6 months for design and permitting and 6–12 months for construction, depending on complexity and contractor availability, and the speed of processing permits.

@Ben LeybovichI think in the perfect world, new investors would spend enough time and energy learning how to analyze properties themselves, what the various calculations mean, etc.