Helping Brother start a construction company

[Nick Rutkowski]

Hello construction people,

My brother and his coworker are looking to ditch their fencing jobs and become an independent company. They're looking to start out fencing but could get into excavating and other jobs needed with heavy machinery.  They want to start their company before the next season starts (NY). Both guys are smart workers and business minded, and have an opportunity to pick up work from the shortage of fence businesses in the area. They want to start small as a two man crew but grow into a large company. 

I'm interested in their business idea and I'd like to partner with them as a silent partner to get them started. Before I offer to invest in them I have a few questions about starting out. They're subjective questions but I'd like to know your opinion and what works for you. 

Would it be better to form an C-Corp, S-corp, or LLC?

Is it better to rent your machines or to purchase them?

Is a separate location for business needed or can they start from out of their garage? 

What marketing did you find effective in gaining more customers?

Thanks.