Great demonstration of the process, Andrew! Adequately detailed and immensely useful. It is certainly something I wish I had available to me when I got started. Thanks.
The inventor of the process @Raghu Kuvempunagar would be able to answer this better than me...but even if you could do it, why would you want a ferroblend negative?
No, at least as far as I can see. For FerroBlend, Ferricyanide needs to be present in the sensitiser which invariably slows down the exposure. Even Cyanotype isn't really useful for in-camera application unless one keeps Ferricyanide out from the sensitiser (as done in Cyano-Rex type processes).
The idea of using cyano-blend comes from me and my Facebook page "The Fascination of Black and White Negatives," which so far only shows black and white negatives. I myself only have one in-camera cyanotype print so far.