[black_eagle]

Issue is not with Mac Kodi app.

No, I know.  I think the issue is with your smb settings on your mac.

Where is smb.conf file stored in Kodi on CoreELEC?

It isn't.  Its on the machine that is sharing the files.

In file, enter [1.MacDOCS]/ instead of [KidsTV] ?
Would path to my external HDD be -    path= /media/sde1/1.MacDOCS  ?
To what does sde1 refer?

1) Most likely yes, although if you have set it up properly, that should already be present in the file
2) No, your path should refer to wherever your Mac mounts the external drive - in the example from one of my shares, the drive sde1 is mounted in /media
3) sde1 refers to a drive in a server on my network and was only meant to be an example of how a correctly shared directory appears in the smb.conf file.