Can I blur or black out faces in a RAW file before sharing it for critique?

Comments turned into an answer...

As has already been covered, you cannot blur the RAW, because edits to RAW are saved as 'sidecar' files & are entirely optional for any other person, app or computer viewing them to use or ignore as they see fit.
There's another downside to RAW - only you know what your intent was; anyone else opening it in disparate software won't even know your start-point. A TIF or JPG will at least look the same to everyone [within tolerance of their monitor, calibration etc]

Unless you really need to discuss skin tones, pets & stuffed toys make good test subjects with no fear of recognition or embarrassment. Or get your subject to hold said pet/toy in front of their face.

If you need to discuss already-taken work for a retrospective post, with no opportunity to replace subjects with toys...
In that case you could blur or black out for privacy & just upload a jpg, with potentially a link to a full single-layer TIFF. No-one could unscramble from either of those if you solidly blacked out the faces - but see Secure way of masking out sensitive information in screenshots? from our sister site Security SE, for caveats if your information is highly sensitive [though I'd usually assume that in most cases no-one would be bothered to go to such lengths]

It's possible to offer potential fixes/cures even from a JPG or TIF by running them through Photoshop or Camera RAW etc after the fact. The changes will not be as detailed as from the original RAW, but they can guide you towards how to make the changes yourself from your original image.

Here are some questions & answers I've personally participated in where advice was gained by using only JPGs posted here & further work could be done by the OP.
None of these had any element of privacy they were overtly concerned about, but the same 'tutorial' approach could easily be taken with hidden faces etc.

What causes this dark halo around the sun? - my own question, the answer helped me find how to fix it, even though I had to do the fix myself.

How can I create this 'medieval look' using an entry-level camera like the Nikon D3300? - the answer to this was done using soft toys, so the OP could copy the techniques later to real subjects.

How could I edit armpit stains out of a photograph? - quick fix to demonstrate the technique, that the OP could then apply themselves to the original.

How to make the signature/watermark look better?
&
How do I correct the huge blue-shift in these images?
- again, rough re-jigs done on JPGs that could be emulated by the OP.

Late Edit:
This one took me a while to find, but this is dependant on being able to read a RAW file using the same software as it was designed to be viewed on. Why does the histogram of an image depends on the software that opened it?