SOLVED: S7 Edge SM-G935S Soft-bricked: Unable to mount all partitions The problem is solved, the solution is posted in the answer:

Problem


The device is unable to mount every partition, this includes:


/efs

/persdata

/system

/data

/cache

The credit goes to member greenman of sammobile forum.
The solution to this problem is as followed:

Following the guide here to flash the stock firmware and Repartition the device.

Here is a full write up of the Repartition process, taken straight from the Sammobile forum website by the member greenman. This is for in case of the website is not available. 

"Here is how to install an S7 firmware

In the S7 firmware Samsung are now providing 5 files.

Phone preparation:
To avoid any issues with FRP (Factory Reset Protection) go to Settings &gt; About device &gt; build number &gt; Tap 7 times to activate Developer options.
Now go to Developer options &gt; OEM unlock

FRP LOCK and OEM LOCK are now both OFF.

1. Download and install Odin on your PC

    [Download Odin v3.11.1][http://dl.sammobile.com/Odin3-v3.11.1.zip]



2. Choose your FIRMWARE by putting in your phone Model version
https://www.sammobile.com/firmwares

3. Download and unzip your firmware (do not use WinRAR as it can give errors)

4. From your download put these files into Odin:

BL
AP
CP
CSC (not HOME_CSC)

5. Now look at the Odin Settings (for this select Options)

F.reset time
Auto reboot

6. Installing another country CSC or a network CSC will need the system partition size changing.
For this select Options and add this setting

Re-partition

NOTE:
1. You will get a WARNING from Odin.
You can ignore this.

2. If you are installing a multi csc firmware, and your existing CSC is in that firmware, then DO NOT select Re-partition.
You can check if your firmware is multi-csc by installing this app:
[https://play.google.com/store/apps/details?id=org.vndnguyen.phoneinfo&amp;hl=en]


3. To receive OTA updates, after installing the firmware, put phone into Recovery Mode to wipe cache then wipe data/factory reset.

A video guide here
[https://www.youtube.com/watch?v=7SK3IMprKVQ]
In the video guide the csc is not being changed and so Re-partition is not selected

Hope that helps."