What year is the MBPro?
Platter-based hard drives often give some indication of impending failure, BUT...
... when an SSD fails, it can just "go dark" all at once -- never to return...
One other thought:
IF you had a bootable cloned backup of your internal drive close-at-hand, you would not be in the pickle that you are right now.
You could have been back-up-and-running in about 2 minutes.
Personally, I would do an initial install of High Sierra onto a spinner HDD. Clone it to a DMG ( a friend here says that SuperDuper 2.9.2 makes a DMG OK ) . Then when Apple sorts out APFS . . .High Sierra 10,13, 6 . . THEN try restoring the DMG to the SSD.
Also, perhaps doing a new CLEAN install of High Sierra to your MacBook onto an INTERNAL spinner 2,5" HDD might allow you to see the drive externally in Disk Utility in the clean installation.
I also wonder if there are any Terminal command solutions that would allow you to see the drive at present.
Please post your progress here for all of us to gain by your experience.
Good Luck !
EDIT : I didn't see your last post ! Glad that you got it fixed. Still I will NOT be installing High Sierra to any of my SSD's 'til Apple matures APFS.