First, I'd like to have switches like on that lamp -- I assume they are "smart", and send an on/off to the Editor, rather than a HW switch. This is an irritant I find on my system already -- wife turns off the lamp manually, and then I have to do the manual "on" before using my nifty app!
On the interface questions, I am of two minds, maybe three. At the most basic level, hybrid reality should make things intuitively obvious to use, especially for basic things; once you get past that, you are in the familiar trade between flexibility and simplicity, and I think going too far down the flexibility path will be a BAD THING. Honestly, for a lamp, or a car radio, I don't think you can get much better than a dimmer switch and volume knob -- and that's basically what a hybrid object would provide. Once you get to more sophisticated control -- hue for the bulbs, or fader and equalization for a radio -- the interface will either get overly busy, layered, or both. Personally, I think when to get to that point, a "designed" interface is better, and an ability to seamless shell into a native app would make perfectly good sense.
For connectivity, I think you're looking at "grouping" as much as anything. A handful of lights that you want to want to work in tandem because they're in a shared fixture or one room, or a bundle of connections you want to hook up at once (hue, brightness, saturation for light, L/R for a stereo, or whatever). I can see this working pretty easily several ways, but the way we're all used to with a mouse is drawing a select box or doing click-to-select and then picking "group".
I haven't played with multiple objects in the window at once, but I imagine it gets busy fast, and hard to connect. Maybe instead there should be a notion of locality, as with the room-specific BT beacons, where colocated devices all show on an alternate page, and you can do simple things from there? Already, I find myself wanting a recently-used page versus having to re-acquire an object.....I have markers sitting next to may chair now to make it easy to pick the lamp across the room without moving.
Perhaps the base set of abilities should include ties to alternate views of "nearby" objects for easy selecting/grouping/controlling/linking? And if an object links to a native app or some other "smart" app, an easy-button to shell to it? For example, on Hue, maybe the page should include a Hue app button that takes you to the factory Philips Hue app, where you can do colors and some sort of grouping already? Or, if you chose to have some of Reality Mixer app for colors, or sounds, or whatever, it would go to it instead?
I am reminded of how musicians behave. A guy with a guitar has a guitar and his voice.....unless he goes one step up and adds an amp (one new object and one new cord), and maybe a microphone (another object and another cord). If you add another guy, he does the same, but by the time you add a third, you add a mixer board and a power amp. And then monitor speakers, and mics for a drum kit, and then an associated lighting board, and so forth. Still, that first guitar has one cord, going somewhere.
Another example is "If This, Then That" -- knitting together existing but single-purpose tools to do something more complex. The app doesn't do everything itself, nor does every interface add much new functionality; the app adds functionality to do simple but useful things.
So, to sum up, I think the biggest value for hybrid reality is to do basic controls on fairly simple but not necessarily well-understood devices, and do simple but clever things with them. For more complex operations, I think some sort of more sophisticated app is going to be needed. I wish I could use the same interface for every TV in my house (volume, channel, on/off, and input would be fine!), and for every media source as well (play, pause, rewind/forward, etc.). Leave the color balance, channel guide, and surround-sound controls for a native app.
As for hue control, I think basic RGB is a good bet. Something that works similarly to what's in Microsoft color picking would be well-known, and in the end that seems like a good bet.