Here you go:
1. Why do I not see any HSE Lux 2016 MY Discovery Sports on the dealer lots ?
I saw a 2015 Lux version in the showroom but could not tell any difference between it and a moderately loaded 2016 HSE.
In Bay Area, there are already many MY2016 DS in dealers' lots: Find a Land Rover/Range Rover Retailer | Land Rover USA
From the outside, 2016 and 2015 are exactly the same. The only differences are that for 2016, all SE/HSE/HSE Lux models have InControl Protect and Remote standard, that's why the base price for all 3 models has increased by about 400. Lux also has InControl Apps standard. Other than that, the only other change is that for 2016 HSE, the standard wheel becomes 18-inch (2015 has 19-inch).
2. What are the nice upgrades between the HSE to HSE Lux ?
Lux has these noticeable additions:
Land Rover Audio System - 11 Speakers
Windsor leather seats
Configurable Mood Lighting
Front and Rear Premium Carpet Mats
SiriusXM® Satellite Radio & HD Radio
Navigation System (SD Card)10
There are other small stuff...
Other than these, most optional packages are available for both. You can find out more by downloading the PDF version of the brochure.
3. Is it worth the difference in cost to upgrade?
For me, I don't need most of these additions, so the extra cost is not worth it. You need to make the decision yourself.
4. How long will it be to wait for an HSE Lux ?
The wait time for Lux should be similar to HSE. I originally ordered a 2016 HSE in early July which was scheduled to be delivered sometimes in late November/early December, but I happened to find one 2015 in one of the local dealers and I could not wait any longer, so I bit the bullet and took that stocked DS instead even though dealers always add many useless options on the stocked units. So I would say the wait time is pretty long.
Hope this helps.