I will start off saying multi hose hookahs are just fine... just try to stay away from the generic Chinese hookahs. The problem most people find with multi hoses is that they are bulky with all the hoses intact, although you can easily get rubber inserts to put directly into the hose port so it's not bulky while the other hoses aren't being used. Yes, it is easy to pass a hose to other people... At the same end it is easy to plug a hose port while not in use. Just make sure that you will have multiple people smoking from it nearly every session as it will get to be an annoyance otherwise. Think about this if you had four people looking to rent a house you wouldn't rent a one bedroom house, would you? Then again you wouldn't rent a four bedroom just for one guy. This is the same with a hookah.
Do a little research on your own... check reviews on brands here on the forums, there is a section specific just for that. NEVER buy a Chinese hookah just because it is cheaper as you will just find that you have to replace that hunk of junk in a shorter period of time over a quality made hookah. The main reason that the cheaper hookahs are cheaper is because they aren't made with the same quality metal and/or cheaper labor that turns into cheaper/poor craftsmanship.
Long story short, do some research yourself, put aside a few hookahs you personally like, compare the pros and cons, then make a purchase. Use common sense.
The Magdy Zidan http://www.thehookah.com/product.php...cat=349&page=1
that you listed is an amazing hookah that will smoke just as good as a Khalil Mamoon, it's just not as heavy since they use a bit thinner metal on their hookahs. The MZ will last you a long time and is very sturdy. I personally own one very similar, just a few inches taller.
By the way, to answer your question about adding another hose port afterwards... No there really isn't a great way to add another port to a hookah without ghetto rigging it.
Good luck with your purchase and remember we are ALL here to help with any questions weather silly or not.