my final thoughts on the timeline before actually going into the movie:
it seems like this is essentially expanding on the idea from loki that a timeline is a collection of branches based around a "root", ie like how loki and mobius travelled back to the 1970s on the sacred timeline supposedly without creating a branch; so logan the film can take place in 2029 on earth-17315 while similar events occur earlier on the timeline in the branch we see deadpool end up in at the end of deadpool 2 (which i still believe must coexist with the original 10005 for deadpool to have created earth-18315)
so it looks to me like this:
- earth-10005 is the "sacred" fox x-men timeline, containing the events of first class, days of future past's original history and dark future, x-men origins wolverine, x-men, x2, x-men the last stand and the wolverine
- the branches of this timeline are assigned numbers as any other universe would be, however im willing to bet that moving forward these numbers will not be used in the same way or even referenced and instead will be called back to as 10005 branches, just as the timeline branches from endgame were never given specific universe designations like 838 was in mom
- earth-17315 - branch timeline starting from the altered events of days of future past in 1973, includes the events of x-men apocalypse, dark phoenix, deadpool, no good deed, the new mutants, and logan
- earth-66250 - branch future where cable travels back in time from 2054 to…
- earth-41633 - branches off from 17315 when vanessa is killed; wase eventually abandons this branch when he travels to or creates various other branches
- earth-18315 - deadpool kills weapon xi in 1979, causing another branch off the main timeline
- earth-??? - deadpool kills ryan reynolds
- earth-??? - deadpool interacts with baby hitler
now, the biggest contention for me here is where deadpool ends up at the end of deadpool 2 when he saves vanessa and peter, and whether or not these two scenes are even in the same branch, and if these two scenes are even in the same branch we see in deadpool & wolverine; with the film glossing over the 2029 date of logan seemingly intentionally im thinking that this is even a further removed branch wherein similar events that occurred in the film logan happened, just a little earlier on the timeline; this can explain how in 2024 this branch can be affected by logans death 5 years later, as its actually happened in the main anchor "root" timeline and therefore all associated branches will eventually die off; this also doesnt provide an explanation as to how he couldnt just bring logan back in time before he is killed within the same branch but might account for the lack of domino and cable; this can also explain how an older x-23 variant can exist, as she stands out among the variants as being the only one we've seen previously in another x-men film that was supposed to be set within the same universe from the outset as opposed to characters like johnny storm or elektra who were always from separate timelines
