I would go for the Dallas flights. Several reasons:
1. Even if not upgraded you get the longest sectors in at least PE and cuts out a bit of time - you can still connect to FLL(or MIA or whatever you prefer) from DFW and arrive in the evening and it's on a couple of hours extra flying (in Y, but hopefullY MCE per status)
2. As noted above pax on the 380 J can be upped to F so one has possibly more chance to get into J
3. A380 operating may or may not have the suites by that point. Probably not, but you never know
I would also try to fly oiver BEFORE that Friday. Several reasons:
If you fly on say Wednesday better chance of upgrade and IF weather or other delays get in the way your cruise is not impacted and you can have a day or two with partner in Florida anyway... surely a bonus?
For ex I would not plan to fly in on the Friday with a cruise starting Saturday. Not from Oz to the east coast.
Coming back, if you could push back to depart easter Monday or even the Tueday a much better chance for upgrade IMHO.