Structure of business

[Benito Sifuentes]

Hello everyone, still pretty new to REI and was planning on tackling investing on my own, but it turns out my immediate family (mother, and brother) want to go in as partners with me. My brother is a broker, and a pretty great at maintenance, and my mother has been a property manager since I was a kid. We figured out that we all bring a different talent and skill set to the table, but we want to start a business for our REI. How I picture it would be set up is that the three of us would be board members hold equal shares in the company and ultimately make the decisions on the company itself. I know my cousin wants to join in but mainly as an investor not necessarily apart of all the big business decisions, and also having four board members doesn't seem wise in case we end in a tie. At least at three there will always be a decision made and not a tie.

So my question would be how would I go about setting something like this up? An LLC? Who would I want to talk to in the state of Washington do ensure the company is set up properly?

Thanks in advance