The Hidden Mist jutsu blocks the sharingan's sight completely; this means both the chakra coloration discerning and the minute movement portion of the dojutsu's predictive abilities. The chakra blends in and all, but the thickness of the mist prevents the sharingan from seeing the muscle movements of the user as well.
Such would be with any 'wall of chakra', albeit, at closer ranges, the sharingan could probably notice movements through the chakra wall (disturbances) and give suggestion that something is causing the disturbance. In any case, anyone masked by something like the hidden mist jutsu would probably attack the dojutsu's complete blind spot, the rear (beyond the periphials) and just avoid the trouble of worrying about close range prediction in the first place.
As far as I'm concerned, if it is thick enough, it doesn't even have to have large amounts of chakra in order to conceal the sharingan's view. Kakashi covering up his always active sharingan is the most classic example of that.
As for the transformation technique, it is most supported that the user would take on the characteristics of whatever they transform into:
http://naruto.wikia.com/wiki/Transformation:_Adamantine_StaffHere, Enma uses this transformation technique to turn his fleshy, mammalian self into a diamond hard staff that can extend and stretch unreasonable far, especially considering his build prior to transforming.
Enma also noted that he could be cut by the Kusangi; it was untold whether this was blood and guts kind of cutting or cutting a hard staff kind of cutting. Many types of transformation techniques, particularly those that transform into living things, can still receive the blunt injuries and such that they would be exposed to normally.
When it comes to non-living things, chances are, if someone were to cut the shuriken naruto was hiding in, dissipation of the technique would be immediate, followed quite possibly by death. It was important story-wise that Zabuza couldn't use his sword to deflect the shuriken, as that might would have injured Naruto.
All in all, judgment on transformation technique, I say you get the properties of what you transform into, more or less.