But the question is - how to colorize dng inside mlv and get the corrected video even after unmount?
Impossible. As I have already stated. You cannot apply ACR settings back into an MLV file. MLVFS gives the impression that an MLV file is just composed of a bunch of DNGs. That is not the case. MLVFS transcodes from the MLV format to DNG on the fly, making it appear like there are just a bunch of DNGs inside. There are not actually a bunch of DNGs inside. The MLV format does not support any sort of method of storing ACR metadata inside.
I don't really know anything about how exactly drastic's software works, but I don't think it uses ACR, so even if you could put ACR metadata inside an MLV file (which you can't), your plugin wouldn't be able to use it anyway.
Like I said previously, the only software capable of applying ACR settings is ACR itself. So if you want to use ACR, you HAVE to transcode out of AE. There is no way around this.
If this is too slow, then I suggest dropping ACR from your workflow. It is not intended for video anyway, and there are much better tools out there for video CC, that are actually intended for that purpose.