A99 flash delay?
Based on your first question, I can confirm from my own testing (F20, F43, F58) that the delay Friedman shows with the a77 and the F20 as a trigger does not exist when using either the F43 or the F58 as a trigger (just as you found). In the latter two cases (the F43 triggering the F58 and vica versa--on the a77), the delay seems identical to that Friedman got with the a77 and its built-in flash as trigger (i.e., longer than the a900 with the F20 or, my experience, the a77 with Pixel Kings), but much shorter than the a77 with the F20 as trigger. So, yes, the F20 seems to cause a problem as a trigger on the a77 in a way the F43 and F58 do not. Is the a99 different? In a comment on his blog, Friedman states he tested the F58 and the F60 as the controller (presumably on the a99) and got the same delay as he showed in his video with the F20. That's really strange: the F20 performs the same when used as a controller on the a77 and a99--a long delay--but the F58 performs worse (Friedman's test) when used as a controller on the a99--long delay--than it does on the a77 (yours and my tests)--short delay. If that's so, some--but not all--of the problem resides in the F20 and the way it interfaces with the a77 and a99--and the a77's interaction with Sony's other flashes as triggers is different (i.e., better) than the a99's interaction with those same flashes. All in all, very strange.