IMHO, once a DB foul occurs , the only DB fouls that could follow are PF & USC. In the OP, the HL was making the call when the FS occurred. The crew needs to decide :
(1) IF the IS had occurred BEFORE the FS, the FS never happened;
(2) IF it couldn't be determine which occurred first, they should cancel;
(3) IF the FS occurred first, the IS never happened.
An example of applying "order of occurrence :
(1) Bubba (OL) tips over in the NZ before the snap;
(2) Tugboat (DL) then kicks Bubba in the babymakers;
(3) As Tugboat sails out of the game, march
off 10 against B;
UNLESS :
(a) A was inside their own 10;
(b) B committed the encroachment followed by A's PF with less than 5 yds to go, B's foul would create a first down UNLESS they were inside B'10. You should
step of the first 5, signal #8, then step off 15 in the other direction, than set the stakes.
If you are still confused, may I recommend a Clam Flats Martini - served at many coastal Maine watering holes
AND REMEMBER...
WHO, WHAT, WHEN,