Tested loss CFC has no QBAI; the computer was, therefore, irrelevant.

There is also no such thing as a GILTI loss inclusion.  See §951A(b)(1).  No, net tested loss does not flow through to the F.1040.

Agree §331 would be the applicable provision.  Treating the foreign entity as a DRE would simplify the reporting but it is not the only and may not be the best option, depending on your client's facts and circumstances.

Why do you think §962 may be applicable?

You spoke of a short tax year but you never mentioned what the fiscal year of the entity was.