This is a long thread and I may have missed why the SH2 can't access the SSD, if so apologies, but if the SSD is a 2.5 inch internal drive you could mount it in a cheap USB enclosure to plug it into the SH2.
EDIT - I see TimCurtis has covered this
It's quite possible that the SH2 USB port doesn't supply enough power to support an SSD drive, have you a flash drive you could try as that requires a lot less power?
It powers my Toshiba 2Tb SSD drive ok.
If only we did know why it will not read it! I certainly would not be dismounting a new SSD to test anything out! I shall, however, be trying a flash drive after Ive done dinner 🙂
Just as a total long shot, it shouldn't have any effect, but make sure you have turned off Smart Setup on the hub.