I have the Mammoth which is similar to the Everest. I have owned mine for eleven months and traveled about 10,000 miles during that time.
My Host has a double DIN Jensen with three sound zones and video output via composite to the bedroom and HDMI to the living room. Sound can be played from a USB or Bluetooth external source. The head unit can be controlled directly, via IR remote or via Bluetooth app on Android or Apple devices. They have just switched to single DIN model, but I have not seen it other than in pictures.
I'm not sure what year they started putting the black tank in the slide, but it is across their model line and works well since at least 2006. It is more inconvenient to have to dump two tanks with separate ports, but the black tank does have a fresh flush if you just need to dump this one.
The Hosts are 8' wide and the Everest uses a full rear wall slide. I would guess the couch is about 7.5'. My Mammoth has a smaller rear slide with a loveseat about 2/3 of that size.
A propane oven is an option if do your own build, but few choose this option and you will not find many used ones configured this way.
The bedroom cab over has a number options allowing a full wall passenger side wardrobe and either king or queen sized residential mattresses. If you do not have the full wardrobe, you will have a sliding window on each side.
A dry Everest will weigh in over 4500 lbs when typically optioned. Once you fill the 60+ gallon fresh tank and fill up all the storage, you can easily be around 6000 lbs. A 3500 DRW is the minimum you need for this camper. if you plan on towing anything with tongue weight or carrying additional items on a hitch extension, you will be over taxing your rear axle.
I have seen this blog from this one disgruntled Host owners, but have not seen any support or encouragement from other owners. I found most are very happy with their purchase and some have bought more than one Host model over the years.
I have a 2012 Everest. I have never used the stereo, so can't help.None of my tanks are in the slides, I don't think Host put the black tank into the side until after the 2014 model.The couch in the rear slide is 70" long.I have the oven and use it often.
I have an East-West bed. The closet (in the front of the cab over), is a little over 7' long, 32" high and 20" wide. I don't own enough clothes to come close to filling it. I have two windows, one at the foot and one at the head of the bed, plus a skylight.
My camper, empty, including the Onan weighs 4318lbs. The Dana 80 axle in the Ford is rated at 11,000lbs. Ford rates the axle at 9,000lbs in my 2011. The rating is lower because of other components, brakes tires etc.
New Fords have a rear axle rating that is higher because of increased GVW, larger brakes, beefier frame, etc.
I weigh my camper each trip. The most it has weighed is 4750 lbs front axle, 9700 lbs rear axle. This is with 35 gallons of water, Front hitch carrier with 400lbs, 4250lbs jet boat and full basement and every drawer and fridge full.My weight can vary by more than 1000lbs, depending upon where I am going and what I am doing.The most my total weight has been is 18,700lbs, truck, camper, boat.
The "Host sucks" web page is rather old. Host has a file that they will show you if you ask. The person who put up the page was pissed because Host would not fix his camper under warranty after he smacked the cab over against something.