@Joseph Gregory I too learnt that this method of activating windows 10 is unreliable after installing it, but I couldn’t even get to activate it using this method as there was an KMS error. Did you manage to activate it the past day?
I think install.wim should be in your USB2(the NTFS one), did you check if your have it in there?
I tried reinstalling win8.1 too but facing “fail to make w:\recycler\scratch directory” error. would appreciate if anyone could advise how to get past this issue.