Kinda why speed is equalized and "D" is restricted from tearing Time a new asshole and Strauss is kept from wrecking the world and keeps Strauss from just going into space, carving up the moon and dropping it on everyone.
Probably. But I guess that's up for a vote or something. Even if Yoshi could hurt these two, he can't debilitate or constrict them. And putting them inside a larger Ketsu would mean none of the others can attack them, which would end up being pointless as "D" could cut through it or Strauss could shatter it. With a concerted effort with Yoshi playing Defense and leaving Hiei, Vergil and Chousinmaru with Kaguro playing offense, it could take a while.
Ultimately it would prolly come down to Hiei's Dragon against these two. At which point if Strauss can't completely block it, "D" will cut it. There's nothing "D" can't cut. And I know that sounds like a NLF, but when it's been consistently proven to be the case, then it really isn't.
Hiei's main ranged are fire blasts from his hands. All of his sword attacks are close range only. Only Vergil has long range attacks with his sword and Kaguro is a close-range fighter only. Like I said, Kaguro will probably be taken out first, followed by Chousinmaru after being pinned by needles. Yoshi may be the next to go if Vergil and Hiei play it safe. "D" can heal from any injury these guys inflict as long as it's not through the heart.
Ultimately, if "D" gets within striking range that's pretty much it for them. In terms of skill, he outclasses all of them put together. And with Left Hand, he can catch another blade using Left Hand's teeth alone with such a grip you can't pull it out. The only Ranged moves "D" has are the wooden needles he throws, a dagger he keeps on his person and his curved longsword which he has thrown to impale opponents before with. "D" can also attach a nearly invisible wire to his sword so he can pull it back into his grip in an instant (much like Jubei has in Ninja Scroll). He did this against his Twin in "Twin-Shadowed Knight".
So, yeah I would say my team wins. Though it would be bloody because of equal speed, so no one is walking away uninjured. But give'em a little time and both Strauss and "D" will be back in full health.