In 25 words . . .

[dash_riprock]

It's not a balk IF F1 steps toward 1st with his free foot while throwing over. F1 is considered on the rubber since he has not disengaged, and neither a jab nor jump step is a legal way to disengage.

It's a balk if he doesn't throw, and only 1 base if he throws it away.

FED permits a jump turn but is silent on a jab step. Until an interpreter tells me otherwise, I will treat them the same.

[Edited to reflect JM's appropriate comment]