Do HX 5-wire oxygen sensors always turn white?
 

I saw this when I was working on my car:

https://scontent-b-dfw.xx.fbcdn.net/...85837812_n.jpg

I am not receiving CELs, except that awesome time that I started my car with the sensor disconnected, but that does not look good!

From looking around the web, this seems normal, at least when the car runs lean, in which case, isn't this actually good?

I wouldn't be worried about a white color... but there appears to be a heavy buildup of deposits. I've never seen that. Did you check the plugs? Anything odd there?

You only recently bought the car, right? Do you know much about the history of it? Any fuel additives? Any loss of oil or coolant?

I have a rear-main seal leak and one other, but they are very slow. In theory, that might be slightly better since I replaced the oil pan. I replaced the spark plugs and wires. I do not remember anything worrisome about them.

I am fairly sure the O2 sensors at the exhaust manifold always turn white from the heat, mine were that color when I took them out for replacement. Downstream after the main cat, it was black from soot.

I would agree with this. IIRC, this is more or less what I saw when I replaced by O2 sensors a year and a half ago. My car is not LB capable, but...