You should've read the part where I said "adjust TP gear to account for haste" which would've saved you a lot of unnecessary typing (it's in my first post).
Well, I'm a DNC with 99 Derpsichore and Twashtar. There's no adjustments to gear Haste that you can make for DNC (after eliminating all Dual Wield gear as I did in my calculations) that make your arguments viable. Similarly, make me a monk set with 10% less Haste that's substantially better than one with capped Haste. What are you going to gain, a few DA%?
For DNC and MNK you should instead use March/Min if you're getting main-job Haste Samba and fighting the same monsters. Your bard should have 95+ G-horn or Langelik and AF3+2 hands. DNC would have to put on some Dual Wield gear, but they can do that easily.
But as others have said, the idea of 4-man farming Dynamis is pretty dumb to start with. The second argument against the viability of Haste Samba is that you shouldn't all be fighting the same monsters if you have essentially 4 melee with March/Min/Haste. Even DCs would die too quickly.