We have rented houses before, but always used a management company.

Did you go direct to seller for this one?

I assume you want to borrow private money to flip houses and not lend on them (?).

Unless the home seller / buyer has extensive experience in real estate THE HOMEOWNER SHOULD NOT DO ANY REAL ESTATE TRANSACTION UNLESS HE UTILIZES THE SERVICES OF AN EXPERIENCED REAL ESTATE ATTORNEY. 

@Omar Maresstart with a house hackif you don't have enough money to house hack, save up enough money until you dohappy to answer any questions you have here in the forumsgood luck

Shocking how little regard people have for a brand new house that doesn't belong to them.

Again because of the same reason.The real problem is that more (social/medium priced) housing is needed which the local government hasn't been investing in for the last 1/2 governing period.

To give a couple examples: a $200k house in the Midwest annual premium may be $1,200 a year and that same size house in the west might cost only a couple hundred dollars.

Together, we negotiated favorable terms with the seller, ensuring a beneficial deal.

Again 20-30% is fair.I have an almost 100 year apartment building where I pay some of the utilities. 60% is a fair estimate and it's often more than that.I have a couple of older houses in 'bad areas' where the tenants regularly trash the property causing thousands of dollars in damage and move out in the middle of the night.