IMO, you should focus on getting af3 +2 out of the way as quickly as possible. It's a very solid set and most of it's items you will use in a lot of sets.
There are some of the items that are rather easy to knock out if you have a few friends with the right jobs, which I would take care of first, like
Hero's,
Goading,
Nieren,
Noesis,
Meridian,
Torque (given you have Shinryu access) and
Veloce.
You can focus a bit more on haste these days as well, since most of the good items also add more defensive/tanking stats than the old stuff.
I've also just seen that you listed Cerberus Mantle +1, which I would change to Valor Cape (as you mainly use it as a macro piece for the enmity and Valor let's you use it also for Rampart).
Furthermore, if you have the inventory and/or gil, you could get
Jingang Legs mainly for Rampart as well and if you, for whatever reason, want to get Torcleaver.
As for 1), I can't think of anything major right now that should be on the list. It contains everything I'd want to get also.
Regarding 2), I would only get it as a macro piece for the fast cast and enmity until Creed Body. But I dropped mine for inventory long ago.
And 3) I would say that Joyeuse still is a very nice sword due to it's high DA frequency and that you should use it until you get a real sword like Almace or Excal even.
I think, if you don't have one of the good swords, it doesn't matter much what other sword you use meanwhile, unless it's a PDT one or Honorbound, which would at least offer you something for your defense.
For the WS gear stuff, I'd just keep the Hecatomb and Twilight items in mind and start optimizing from there.