We stayed at this riad in Marrakech: http://www.riadkniza.com/
It's just inside the walls of Old Medina, so all the old city stuff (souks, historical sites, main square, etc) is very walkable, and it's also easy to leave the walls to check out the "modern" side of things which you'll likely want to do for some dining options. We did the hammam experience on site which was really cool, and they have a nice rooftop.
The owner was very nice and served as our guide on a walking tour (not free, but worth it). I would not say he helped much on the haggling front. That was left to us. That can get stressful, but we had fun with the experience for the most part.
Last thing I'd say is 7-8 days in Marrakech sounds like a lot to me unless you really are just planning to sit by the pool for a good portion of that, or if you plan on doing a ton of shopping.
We were there during Ramadan. I would recommend trying to avoid that. It's weird eating and drinking during the day in front of people that can't.
We didn't go anywhere else in Morocco as this was the end of a month on the road (spent mostly in Spain), so I can't help with the other questions.