All of your ideas are very interesting, seemingly focused on interaction between technology, dust, and semblance.

Sanguine Channel, if I'm right, uses the user's blood mixed with dust to give its blade extra effects.  Sounds very painful for all sides involved.  It might be worth noting that the existing character Mokuren Sabella also has a sword that has bonus effects when empowered by blood.

The Iron Maiden is probably one of the most original ideas I've ever seen.  One mode for absolute defense, one mode for absolute offense.  I like the idea, but it seems more plausible to me if the defense form of the weapon were simply a huge tower shield, rather than a complete suit of armor.  Your call either way.

Masamune is my favorite of these.  True to its name, it gives me the impression of a legendary Samurai.  It is a simple weapon, but one whose special ability allows it to nullify the dust-based attacks of others, forcing opponents to fight on the user's terms.  The added effect of the semblance brings to mind all of the epic scenes where two Samurai clash, strike through one another, and then one falls a moment later.

Unfortunately, Cacophonys is my least favorite.  It seems to be both the weakest and the most nonsensical.  If it were a firearm of some sort, I could very well see it existing in the RWBY universe, but a phone?  Less than ideal if you ask me, which I assume you are.

Keep up the good work!

@Tear, he was online five hours ago.  I assume that he's under the impression that the collab is finished, and he's waiting for you to post it, but I'll let you decide.