Things to do before HW?

Assuming you have all sidequests etc completed. I'm thinking of:
* take and complete 16 battle and GC lv.40-45 levequests (it's max allowed) on a class which you want to level first. Turn them on HW launch day and you'll probably instantly get half level XP.
* take and complete 6 Ixali quests, turn them on later for a a good XP chunk for your lv.50 crafting/gathering class.
* cap soldiery (in case if it'll be converted to poetics), GC seals (for GC rank up), possibly Hunt seals (for new vanity gear if there'll be any) and Wolf Marks.
* buy or spiritbond crafting/gathering materia for new lv.60 gear.
* craft or buy lv.25-40 gear for new jobs.
* reserve around 5 mln gil for new HW vanity gear or minions if you need those.
* stock ventures for leveling retainers or for new exlorations.
* clear your inventory, new main scenario missions will likely reward with V materia and other valuable items and you'll not want to miss them.
Any other ideas?

I capped my GC seals long ago; I want that rank-up ASAP. The rest seems like lot of work and I'm pretty lazy already, but it's a good idea if you want that boost right out the gate.
Also I sorta wish we could trade level allowances... I only need a few more for my gathering title...but I digress.

Maybe try to clear out your Retainers' inventories? So you have more room to hoard new stuff.
M... I can't think of anything else that you haven't said already...

Finishing Ixali would be a good start since we are getting new Beast Tribes in 3.X era.

Not to mention this would lead to the continuation of the Beast Tribe Alliance so getting Part 1 of the Beast Tribe Alliance Saga finished would be ideal if you're interested in the Beast Tribe Storyline.

As for other ideas....

Probably level any DoM or DoW you have yet to reach lvl 50.

beyond that your list covers everything basic.

extra could be leveling of your Chocobo companion if you want for your exploration of 3.0 zones since 3.0 area monsters are going to be tougher than 2.X era monsters.