Re: A couple of questions !
I'm not sold on the electric coal thing, as I haven't seen a lot of great reviews.
As far as Herbal Shisha, there hasn't been any real research into the health differences between Herbal and real Tobacco based shisha. I would say most people find that smoking the actual tobacco based shisha's are more enjoyable (better flavor and such), and the only big difference I'd see is any nicotine buzz you might experience.
As far as hose number and autoseal, I'd say that a one hose pipe will work great for 95% of people. Unless you have a really massive group of people (5+), one hose should suffice as you want to sorta take your time smoking. It should be more about atmosphere and enjoyment rather then just hoovering as much as possible. The issue with autoseal hoseports is that they are usually pretty restricted, and you cannot purge the hookah should you want/need to.
As far as the smoke's effect on the room, the smell may last for a short term (day at most), but then it will fade. I smoke in my room quite often and there has been no lasting effect, compared to say cigarette smoke.