I'll reply to my own message, and I suppose I'll give myself credit for solving my own question too. Question 1, I didn't need answered, since it only took three screws to remove the internal wifi card. Question 2, it has two antenna.  Being a low end card, it's what they call 1x1, meaning loosely each antenna only sends or receives, not both.   At the moment, I removed the internal wifi card, and I'll run a few weeks on the USB wifi dongle.  If the computer makes it six weeks without a freeze (that's about the longest it's EVER gone), I'll start celebrating.   Also... SIX nagging automated bot emails from the forums for this one thread?  Six?  That almost qualifies as junk mail, if you ask me.
My inspiron 5559 has been impossible to depend on from day 1.  I didn't use it much at first (I had a work laptop, etc.) so I didn't return it in time, and since then, I don't (and can't) use it for anything important, because there's always the risk it'll freeze on me.  (When it does, it leaves the fan running and whatever was on screen at the moment it froze. It no longer registers as connected to my router, and nothing but powering off gets it working again.) After 4 years of this, and after trying everything imaginable, I came across one other person who had the same exact WinDBG code as me, and they (maybe, sometimes people celebrate too early) said that something was wrong with their Intel AC-3160 wifi card, and everything was fixed with a new one. (In this case, the person never came back later (like most people do) to say it wasn't really fixed, so I'm hopeful.) So two questions: Thanks in advance
Inspiron 5559 - Disabling current adapter - And is there room for 2 antennas if 
I upgrade from AC3160 to AC8165?