It wouldn't seem that it is no.
The description is all wrong for a start
not really the milky white of cuendillar.
Not that we know what Callandor is actually made of, could be something similar I guess.
As far as I can tell its not explained anywhere, its seems to be informed knowledge that the One Power (even balefire) reinforces the cuendillar.
Moiraine just kind of plonks the info out there
Possibly some kind of knowledge kept inside the tower perhaps, but it doesn't seem to be explicit...
At this point the only material capable of being transformed by Egwene's weave is iron specifically.
Now I hesitate to rule out the possibility of using another base source with a different weave as there's always the "you never know" factor with new weaves and so on.
So I'll just say under...
Should be reasonably similar to the iron its made from I assume, and it can be made thinner too, so it should theoretically be lighter than than an equivalent steel armor.
The interesting thing to me, is how does cuendillar react when struck, and unfortunately there is precious little evidence...
Cuendillar armor is certainly possible, although tricky.
You have to make each part separately and then lash them together usually.
Anything touching each other fuses together so you have to be quite clever with it, but most armor is possible depending on how you go about it.
Platemail...