Magnus,
Lest you think we're all unfriendly here, let me just point out that you've asked for an AWFUL lot of information. Like many other people here, I suspect, I'd be happy to help you but I'm not going to devote an hour to answer all of those questions in detail.
I suggest that you contact your local Segway dealer (whoever you would buy them from) and ask all of your questions - and then come back and ask the few questions that might be better answered by an experienced tour operator.
And ask one question at a time
People might jump in with an answer to one or two questions when they don't have time for a dozen.
Good luck with your business.
Respectfully,
-Bob