ASM@3 1 is definitely after ORIGINAL SIN, so cool! Things are shaping up.
So, X-Force v4.
#1-4 were published before ORIGINAL SIN. #5-9 were published during ORIGINAL SIN. #10-13 were published during AXIS. #14-15 were published after AXIS.
Flashbacks through the volume starts the whole deal. These flashbacks happen "a month" before #1 (Cable, Hope, Marrow and Fantomex "join" the "team" here). #1 happens in a day; Psylocke is recruited here and it's her first mission with this version of X-Force.
#2 happens over a day or two, no mention of how long it's been since last issue. As noted earlier, Wolverine & Storm (who don't know Psyocke is on Cable's team), Mystique (at the Hand HQ?), Polaris (in her Serval Industries suit, same month as ANXF 4), Magneto (in his black suit), Havok (at Avengers HQ), and Cyclops appear.
#3 happens "20 days" after #1. Psylocke is still active with Storm's team (along with Monet, Rachel Grey & Jubilee), so that's nice. Probably a few days after #2.
#4 happens in a night, probably the day after #3.
#5-6 happens in a day, shortly after #4. Probably a few days after.
#7 happens in a day, shortly after #6. Probably the next day. Domino gets captured by Mojo here (disguised as Arnim Zola), and can't make any appearances elsewhere until she's rescued later in this series.
#8-9 happen over three days, some time after #7.
#10 picks up shortly after #9, and spans a week or two.
#11-12 happens the day after #10, and happens in a day. We're now "five months' after the flashbacks that start the volume. Domino is rescued and Fantomex goes crazy and becomes a villain. In #12 Magneto appears again (same month as Magneto #12, an AXIS tie-in) as does Storm (same month as Storm #5).
#13 starts some time after #12, at least three days later but probably closer to a week or two, and happens in a day.
#14-15 happens some time after #13, possibly weeks later, and happens in a day or two. Fantomex is basically "reset" (but kicked off the team). Then, there's a break of two weeks during #15.
Psylocke can appear in other books during story breaks in this series. That's great.
Fantomex is trickier. He's basically crazy (or more crazy than normal) as of the "month ago" flashbacks that start the whole series. However, he appears as a teacher at the JGS over in Wolverine & the X-Men v2. Sporadically in issues #1-8, and then in #10 after Wolverine's death. In theory, that means this volume needs to happen between W&X2 8 & W&X2 10. Not so tricky, I guess. W&X2 1-8 are already placed well before ORIGINAL SIN.
Domino appears in the latest Punisher volume, but that's after ORIGINAL SIN. Something to keep an eye out for, but that would suggest XFOR4 7 is after ORIGINAL SIN as well as after Punisher #6. She also appears in the latest Deathlok series, but again, that's after ORIGINAL SIN, and that wrapped up after X-Force did.
Cable appears at Deadpool's wedding in DPOOL5 27 (same month as XFOR4 3), acting just fine. This is most likely before the "month ago" flashbacks. DPOOL5 27 is already placed after W&X2 1-8, so that's nice.
So our start point is after DPOOL5 27, and our end point is pre-Death of Wolverine (which is before AXIS). Putting Cable, Domino and Fantomex together, we have:
W&X2 1-8 -> DPOOL5 27 -> ORIGINAL SIN -> Punisher #1-6 -> XFOR4 7 -> XFOR4 15 -> W&X2 10 -> AXIS
Looking at X-Force's timeline:
flashbacks (a day)
-a month later-
#1 (a day)
-three weeks later
#2-7 (about a week)
-some time later- (assuming two months or so)
#8-10 (a week or two)
#11-12 (a day, five months after flashbacks)
-two weeks later?-
#13 (a day)
#14-15 (two weeks)
If #2-7 happen in about a week, and #7 has to be after Punisher #1-6 for Domino, which is after ORIGINAL SIN for Punisher, it looks like only XFOR4 1 (and the various flashbacks) are before ORIGINAL SIN (in theory, ORIGINAL SIN would happen during that "20 days"), and XFOR4 2-15 are between ORIGINAL SIN and AXIS. Also, XFOR4 1 would be closer-ish to ORIGINAL SIN, with the flashbacks being a month before that. #2 was published the month before ORIGINAL SIN started, and the same month as All-New X-Factor #2, so I guess we'll see how that line up.