My plan is to secure the permits for the lot split and the new construction before I approach a builder.

I can handle that, I'll make extra payments to make sure I'm a couple months ahead just in case disaster strikes.  

My question is how to come up with financing for this $15k ( I can't put down $15k extra at the moment) .

If the property appraises for $100k you will only be able to cash out at 75% LTV - $75,000, so maybe you can pay yourself back and pay off the credit card and have a couple grand extra.

Our best work is usually done by hiring individual handymen and subcontractors to pull specific permits as needed.

I work 1, and I do a few extra side businesses to bring in money.  

If below market, that’s some extra tailwind that can help you as tenants either vacate or leases renew.

., Texas/Utah) if you are permitted to work remotely for a portion of your time to reduce your CA state income tax burden.

It might cost an extra $2k, but having that sound proof layer might save lots of headache from tenants calling to complain about noise from the upstairs.

Peter if you go new subdivision pay attention to the size and solvency of the builder.The small builders that do one off homes or small to mid size cluster subdivisions those are the ones that usually can be in big trouble if an economic shift happens.Look at new build permits coming online for the area and the price range you are looking at.The big builders tend to be more experienced and can still finish out  projects with down turn so you do not get left with a pipe farm development where some homes and some empty dirt parcels.Nothing is foolproof but this can help.