OK, now I have some time on it and some tanks of gas run through... last tank was 38.3 mpg, better than I'd expect given the conditions which included a bit of "conservative following distance" semi drafting at 65 mph. I know the "evidence" is anecdotal at best, but surely at least some fraction of an mpg gain was because of this mod. Can't make any more accurate fe benefit claim at this time however I can also note that the car seems somewhat quieter and maybe (placebo effect?) a skosh more responsive power-wise too (slowmover was right!).
100 degree temps + grille block + efan
delete = no problems at all, so far.
(High temps + a/c delete also lead to making the whole trip with the moonroof open which may affect aero a skosh).
I might take the power steering delete to the next level and loop the lines, although it is entirely manageable as is.
Now I'm eyeing the accessory drive on the F150 to see what else (besides the mechanical fan that's already gone) I can throw away there...