DTC Codes, Fixing and Clearing

I was looking through the test menu on my 2012 keyless focus when it showed 2 DTC codes:

     DTC #1: C415_64  - which I believe translates to u0415 - Invalid Data Received from Anti-Lock Brake System (ABS) Control Module
     DTC #2: C422_64  - which I believe translates to U0422 - Invalid Data Received from Body Control Module

I don't have any warning lights showing on my instrument cluster, and I've not experienced any braking issues. A friend connected their OBD reader and did a scan, it returned the following:
    C0037, C0034 and C0031 which are described as ABS mechanical errors on the Rear left, Front right and Front left speed sensors (ABS.jpg)

we then did a full scan, and in addition to the above it also reported:

     B1A79 described as related to Body control module, an intermittent open circuit on the Rear Fog lamp (B1A79.jpg)
     B10C9 described as related to Remote function module, a Pending circuit failure on the interior front antenna (B10C9.jpg)

We reset all of the error codes, and I took the car for a quick drive and when I returned we checked for any errors.  The OBD scan returned green (Cleared.jpg), no errors however the two DTC codes are still being shown when I check via the test menu (DTC1.jpg and DTC2.jpg), despite a second ODB scan confirming the codes have been cleared.

I'm going to drive the car for a week or so and then rescan to see if they come back, but I have a couple of questions int he meantime:

1) Is there a reason the DTC codes are still being displayed in the test menu despite being cleared by OBD?
2) I'm surprised with 3 potential ABS sensor failures that the ABS light didn't come on, do you know why this may be?
3) If the ABS mechanical errors return, I assume given the error its just a case of replacing the three ABS sensors? Does anyone know where I can source the correct replacements?
4) Does anyone know if there's a "typical" cause for the B1A79 and B10C9 errors, and/or can offer quick guidance that I can work through should these faults return? (I assume the front antenna relates to the keyless entry antenna)

Googling the B1A79 and B10C9 errors I did find a some diagnostic pages but they were for a Mazda, they looked appropriate though, would these be relevant?

Hopefully the issues won't return now they've been cleared.  Any advice/guidance would be greatly appreciated
Cheers

Nimp