Does QNEC to pass ADP trigger gateway?

Participant does not qualify for a PS (term < 500 hrs).  However, plan fails ADP and he's getting a QNEC in lieu of HCE distributions.

Does that QNEC trigger a gateway?

The gate way is just for cross testing.  So, no.

If you have cross-tested PS then I would say yes.

Yes.  the QNEC triggers gateway even if participant does not qualify for the PS. 

So, if it's in the Gateway, is it in the general testing?  I thought I read somewhere that ADP QNECs are included..

As I recall, a plan has to pass testing with and without the QNEC. I guess you can't cheat on the original allocation. normally HCEs don't receive QNECs so passing with a QNEC is less of a problem.

A gateway is required only if you cross test the allocation. (I don't think simply running the avg ben pct test triggers a gateway)

but if you can pass testing on an allocation basis then no gateway