1. Yes.
Page 199; "Sensor is a rating representing the suite of information-gathering or detection devices that are built into every vehicle in the Sixth World."
Page 445; "Most vehicles and drones come factory-equipped with a sensor array (at a rating listed with their stats)."
That's pretty clear to me. Just because the first paragraph doesn't specifically mention drones do not mean they are excluded from that rule; drones are still vehicles, and they still have a Sensor rating.
2. See above reference to page 445. A sensor array always has capacity 6.
3. The housing is the drone itself, see 2. The problem is that these rules contradict themselves; the phrase on page 445 specifically states that a sensor array "at a rating listed with [the drone's] stats" comes factory equipped, meaning all drones come with a rating 3 sensor array (all drones in the SR5 core book have Sensor 3). The table for Sensor Housings on the other hand has Large Drones listed as Max Sensor rating 5.
In my opinion, then, drones come with up to 6 free functions from the factory limited to rating 3 sensors; for a fluff justification of this, think mass production costs vs individual costs.
So, if you wish to upgrade the sensors on a Large Drone to Rating 5, for example, you would then have to pay Rating 5 x 1000 for the array (page 446) and then you'd get to pick 6 functions for the array at Rating 5.
4. Page 446; "If a function has the same name as an imaging or audio device, it’s the same as its description in those sections, with a Capacity equal to its Rating, and thus is not described here."
Meaning, yes, you can put a camera in a sensor array and then upgrade the camera with vision enhancements. Keep in mind that a micro-sized camera only has capacity 1.
5. Incorrect; there are four ways to control a vehicle, three of which applies to drones (see page 265)
1. Manual Control (does not apply to Drones as far as I'm aware)
2.. Remote control (can be done even with a commlink, so a street sam can have an eye-in-the-sky for example)
3. Autopilot (using the drone's Pilot rating)
4. Jumped In
By the RAW as per page 270, the drone would use it's Pilot + Clearsight [Sensor] to observe it's surroundings in the case of 2 and 3, while you would use your own Perception + Intuition [Sensor] if you're Jumped In. And this is why it's a good idea to upgrade a drone's sensor array if your drone is medium sized or larger

6. I'm not sure where you're getting this from. Page 270 as per the above states that "Either way, you get to use the drone's entire sensor suite, if it has one". Using Electronic Warfare is an option that you can always use when making a Perception Test with Sensors, as per page 445; "When you use the sensor array for Perception Tests, you may use your electronic Warfare skill in place of your Perception skill, and you may use the sensor's rating as your limit".
I'm not sure about compiled play examples.