There is no evidence of any upper memory manager in config.sys, so you are indeed stuck with just the base 640K memory.
Check your DOS image to see if there is a copy of HIMEM.SYS available.
Then add DEVICE=HIMEM.SYS as the first line of config.sys.
For the subsequent DEVICE entries, try DEVICEHIGH and watch for any load errors. Not all drivers will load high, but if they do, it releases some base memory for use by other files.
In AutoExec.bat, stick a REM in front of the line which loads the mouse driver, to stop the mouse driver loading. This also releases some memory and you can still drive Ghost using the keyboard rather than the mouse. You can also try loading the mouse driver high which preserves the driver without using base memory.
To load the mouse driver high, try if exist MOUSE.COM LH MOUSE.COM
Again, if the mouse driver will not load high, remove the LH
You can stick a LH in front of the netbind line, so it looks like LH \net\netbind.com
If netbind does not load high, then remove the LH.
Yes, it does involve some trial and error, but it is usually possible to free up enough base memory to get the DOS stack working again.
Moving to WinPE as the boot environment gets around all these memory issues that you get with DOS and also provides a mechanism for using windows drivers to support modern hardware which DOS is increasingly unsuitable for.
Make sure you have run LiveUpdate so that your Ghost version is at 11.5.1.2266