I mean, if I co-sign, then does it give me any power to sell one of his land there to recoup money and rest goes to him?

In short, to achieve and maintain financial freedom.

My ultimate goal is to develop land once I have enough passive income and financial freedom.

House hacking is a powerful strategy that can put you far ahead financially compared to those buying a primary residence or continuing to rent.

This is a great step to financial freedom, i would said what really change my game is using an investment loan that allow me to buy property that generate cash flow without have to show my income.

You will not have the existing power supply that I assumed.Still I like @Jill F. idea of installing mini-splits.

My wife and I are 28  year olds, living in Southern California and we are starting to create our financial freedom portfolio in real estate.  

Syndicators who brag about their instagram lifestyles without a big old pile of exits... probably bought that lifestyle with their investor's money, whether Ponzi scheme or exorbitant acquisition/management fees.That... or selling high ticket coaching items on the power of real estate.

I'm also wondering if anybody knows the costs and rules for bringing in water and power to a piece of land in these areas, I know it's different for each property but is there any possible way to get estimates on bringing in water and power to a piece of land I want to purchase before actually buying the property so I can create a general budget for buikding a home.

Its powerful, and can be as complex as you want it to be.