Hi Marcus,
You'll be lucky if anyone would be able to answer all that in one post.
It might be an idea to break your questions down into seperate threads. Surely you've got some idea of what chemicals your thinking of using?
There's also alot of info if you search the forum.
Please don't take my reply as being unhelpful , i'd be only to happy to help you We do EOT work as do a few other people on here, but that post looks like you've done absolutely no research whatsoever.
Steam cleaners are handy, but when your starting off your best to spend as little money as possible. So unless you've got a large budget, i'd forget about buying one until you've made some money.
What area are you in?
Arthur