Small Business Tax Questions

I own a new very small bee hive farm with a partner. We only have 1 hive so far and don't plan on showing a profit for at least 3 years (until we can buy at least 3 more hives) - Do we both need to have separate EIN numbers for the business expenses for these first few years or can we use 1 EIN (we've separated all the expenses & receipts up to this point? 

 

Also - do we need to worry about an LLC until we actually have significant profits?