There's still no evidence of this. You're making an assumption.
Hardly.
If it needed benemite crystals they would have mentioned it.
The crew was quickly able to adapt the technology to VOY with some Warp core modifications. Again, there was no mention of Benemite crystals that Arturis Dauntless needed it (and also, one would think that the crew wouldn't want to canibalize the Dauntless crystals when the crew was told in the fake message that they're supposed to stay in Slipstream for 3 months).
Plus, there was sufficient deviation between the two versions of the technology which can easily explain the first version would not need benemite crystals, whereas the second one would (because it was essentially an extreme modification of the baseline technology and sported various technology that v1 never had).