16" tires usually have a higher weight rating, so that's a benefit. Also you can get LT tires in 16" sizes more easily, if you are of the mindset that LT tires are better. Plus, at the same speed the 16" tire has slightly less revolutions per mile. Even though the 2016 model doesn't have the bigger wheels, the dealer can upgrade them for you if you are willing to pay the price.
I don't have a backup camera on my trailer, but I often consider adding one. It makes backing easier and makes you less reliant on a spouse... therefore less likely to be fighting upon arrival at your destination
... don't ask how I know!!!
If you can get a good deal on the 16 and want to camp NOW, go for it. There will always be new features and options on newer model trailers. Buy what you like and don't always be chasing the newest model or you'll go crazy.
Can't give any advise on a 5th wheel hitch, we tow bumper pull still. If you have a 6.5' bed or shorter, its probably wise to at least consider a slider hitch. New 5th wheel trailers often have rounded corners to make them "short bed accessible", but they can encroach upon your truck's space if you are backing and at a tough angle.
Good luck in your decision!