I would love to help a skilled tradesman but I assume the schedule would not be flexible enough.

Is there any lender that will be more flexible?

@Andrew Freed Somebody else brought up this same idea to me - using the flexibility of a HELOC (and ability to make a cash offer) to secure the property, and then later paying off the HELOC with a fixed rate mortgage at a later date. 

Most accounting packages are fairly flexible so you'll need to customize it to your business needs.  

Furthermore, the lender is private and is more flexible in allowing people to get mortgages with not-so-good credit.

Do you think that 30% down flexible?

While your Roth is "locked up" until you are 59 1/2 except for your contributions, a brokerage account is flexible as in you are not limited on what you can invest in.

However FHA is pretty flexible, and if you have stronger credit and down payment a Conventional loan would also allow you to use rental income to qualify.

A lot of times direct lenders can offer you much better rates, pricing, and are much more flexible on terms than big box lenders.

There is obviously some flexibly with that and every lender is different, but your intent must be to use the property for primary living.