Bring debuffs. I know right, more content where debuffs actually matter! Def- and Atk- are a godsend as always.
It is a damage race, so the most important things are to survive and to have enough damage to get through 225m HP (plus overkill damage) within 100 turns, despite having your damage output nerfed bad in P2 and P3. Remember, Heavenly Wind Disaster is out! There are not many out there yet, but it's a huge damage boost if you can find yourself a MLB one (and you're using Machine Beast/Hraes/Hanu yourself). You can infinitely keep entering and Give Up Heroic fights, so abuse that once you're confident you can do it with HWD.
Ascle is very strong for this fight, as she is the ideal Target. Not only is her passive Regen quite strong, but she can also single target heal for large amounts and generate potions for even more safety. However, keep in mind that Ascle is S L O W, so in P3 when you need to do ~75m damage with Bursts... well. If you can't speed up Ascle, you'll probably end up rotating 4-bursts and 5-bursts.
Parac is the true hero of this Heroic, IF you can survive without Soul heals. Since Wind heals are quite limited (Set and Frigg, also Azazel), this can be a huge issue. Anyway, IF you can use her, Parac will largely trivialize the entire damage race portion of the fight. In P2 you can just forget Full Bursts entirely (unless you need them for Burst effects, like Cu and Azazel are really strong) and just normal attack Rahab down. In P3 you will FB significantly faster, so you won't have any issues.
Paras is of course a good option too, as she can deal ability damage (1), normal attack damage (2-A) and even work as a healer/damage sponge for Target (3-C), and her guaranteed Combo passive will let her Burst fairly fast as well. If you have her Soul weapon, her -30% Def debuff will probably be a huge help to you as well.
Caspar can be used for debuffing (3-A) and healing (2-A) as I don't think that Rahab will remove Snatch stacks. Remember that 2-B is a ridiculously strong buff if you don't need the heal. Anyway, those who have Set instead of Frigg might find Caspar their go-to option here, as Set+Caspar with Ambush is -50% -50% by themselves, with possibly double heals.
As for Hime, Azazel and Gaia truly shine here. Azazel is of course a massive powerhouse as always, but -30% AoE damage cut and Regen and HP leech are a HUGE savior. Strong Wind players might not even need a healer with her around. Gaia can entirely negate an Overdrive every 6 turns, and almost entirely negate another one every 6 turns - or better yet, use that against Triggers. Frigg is also a treat to have in this one, due to having heals (it is a long fight!), debuffs and debuff Prevention. Sniper Shot might be a great EX ability to use with Frigg as that's -40% -40% already. If you run extremely defensive team comp of Frigg, Azazel and Gaia, you can just shrug off just about everything that Rahab throws at you. Just keep in mind that turn limit - Azazel can speed you up, so make sure you make good use out of that too.
If you don't have single target heals (read: Ascle for Wind), Eidolons can be used whenever Target gets to low HP. However, keep in mind that for P3, Northern Star Lord and Byakko are amazing to have, and for P2/P3 Southern Star Lord will carry hard. But the more of those that you bring with you (if you even have any, heh), the less Eidolons you have for Target swapping.