Problem finally solved, though I had to use a big hammer. No, not a literal one. I installed vanilla Windows 10 Pro on the system, waited about 15 mins (because win 10 will install drivers in the background), then installed the device drivers that Device Manager showed as missing. It's been a week now with zero fan pulsing.  Now that the fan issue is resolved, I am really liking the system.
Using the Optimized or Cool power settings in the BIOS version 1.5.0 (don't want to use the other settings), the fan keeps pulsing on when the system is idle. It's on for 1/2 a second, then off for two seconds. The result is whrrrrr..... whrrrr..... whrrr.... after a few minutes I want to take a hammer to my new laptop.  The only solution I have found so far in the forums is that someone mentioned disabling the i7 cpu's speedstep feature. I haven't tried this solution, as I should not need to lower machine performance to make a fan stop stuttering like that.  Dell engineers: some hysteresis or delay would really help here. In other words, just keep the fan on for a bit, to permit the system's temps drop below a lower threshold, or keep the fan on at a lower speed. This is pretty important human factors issue. Not a technical issue -- a human factors issue.  HELP. I'm really ready to sell this on eBay if I can't get an answer. Thanks!
G15 5510 fan is pulsing every 2 seconds - incredibly annoying