The speed limit sign recognition feature was standard on all the X1s ("Speed Limit Information via On Board Computer within instrument cluster" in the brochure) back in 2016 when I bought mine, so you should get that. But the folding mirrors, electric seats and front parking sensors were all options I think. You should also get sliding rear seats as standard on a 2016 model, which are now an optional extra, and probably the enhanced interior lighting package, which again is now an extra I think.
I've got the "standard" nav in my 2016 xLine, with the smaller screen, and I've found it quite adequate for the last 3 years. I would have liked the larger screen, and the accompanying Heads Up Display, but I couldn't justify the extra grand or so on the order.
One option we couldn't really do without are the electric adjustable memory seats, as my wife and I swap in and out of the car regularly. I also specced non-runflat tyres, along with a spare space-saver, electric folding/dimming mirrors, sun protection glass, a heated steering wheel and front parking sensors with the rear reversing camera. Those were our priorities at ordering time
If money had been no object then I would have gone for the larger nav screen, probably a sunroof, and a better sound system (ours is the Basic one). But those would have added probably another £2.5k to the cost!
The 2016 xLine already had LED lights as standard, as did the M Sport, and leather seats. I've got a PDF of the standard specifications for the 2016 models if you're interested? They did change slightly over time; I've got January 2016, July 2016 and November 2017 if it helps.