Been a while since I had this one on the table, but if memory serves...
I was wondering, when are units marked with RF markers so that they may be fired on during the Reaction Phase?
There's an RF result on the Fire Table, and it is that result that would cause the units to be marked with the RF marker.
Also, could you please clarify how to conduct the Union Special Sequence after Turn 4 (6.6, 14.0)?
Those Union Units (only) enter the map, moving their full movement allowance. That's the entirety of the sequence-- it's just the guys coming into play.