Can I use an inductive load in an ATX-to-bench supply project?
In this case, you're fine.  Of course there are already a bunch of inductive loads already in the system, but also the inductive loads only play a part when the supply turns on or off.  Inductive loads only show their "inductiveness" when the current changes, and since the load is going to have a constant current then you're all right.

If you want to be extra careful, you could put a diode between your output and GND (oriented so it's not normally drawing a current).  That would protect your power supply during turn on/off from any inductive kickback.  Even if your "minimum loads" were not inductive, this would be a good idea just in case you want to connect motors or whatever to your benchtop supply.