So...2 boxes (rsw04 & 05) have Titan power panels, Titan front panels, and Viper CPUs. With testing, I found that the DC-DC control was not being driven by any of vio 0–7 (though vio 3 controlled the Aux power). With the DC-DC control not driven (and thus at 0V), the DC-DC converter wasn't enabled to provide +24V to the Ubiquiti. Thus, I came up with a hack of using wire-wrap wire to insert +5V to the "Titan J3" connection on the power front panel. This successfully turns on the DC-DC converter. However, since J3 is now not connected, we've lost vio control of Aux. Thus, I also changed the Aux FET jumpers to leave Aux always on at +12V. (This probably wasn't necessary, since the Aux FET control has a pull-up and was on anyway, but it seemed the proper thing to do.)
I haven't mapped out the other vio ports to determine which/how ttySx are controlled by vio, but it seems to differ from what vio reports.
Even though rsw02 has an actual Titan, I did the same wiring on that box as well. Perhaps vio would have worked...