Butterfly Labs is a complete non-starter for mining gear. They haven't been viable for the last 18 months or more.
This seems like quite an undertaking as a first time mining farm. It will be at least a month before you an get the infrastructure setup and the miners delivered I'll bet. That's two difficulty increases. My expectation is that those will be at least 8% each (if not more).
You are also aware that the reward of 25BTC/block will be cut in half, roughly in June of 2016?
I would not believe in free 40-50KW of "free" electricity. Maybe cheap in some places but not free.
OP I think you really need a business plan. For 6 figures you need to really have that plan very solid, and trusted.