Can you convert 6 mill threads to mh/s?
No. I don't have any of the GPUs in KernelAnalyzer's group of simulated GPUs. I have only this Radeon HD 3410. I assume it's roughly 4 hashes per thread, so 6 Mthreads/s approximates 24 MH/s. Probably less because of runtime overhead.
Also, these 5 bitcoins...5 bitcoins per person, or it could be small donations from everyone to make 5 bitcoins?
Let's say 5 BTC per platform.