You can do this but connect a TS plug/splitter to the 8 Steps output instead of the TRS splitter. You want to use the 8 Step’s output as a Control Voltage rather than as an expression output.

The problem with using the TRS splitter and splitting the expression output is that the 8 Step receives voltage from the pedal it’s controlling on the Ring connection. If you short the ring connection between two different pedals it could cause problems where you’re shorting two different voltage levels or the voltages are each trying to drive the other one, a part could burn out inside one of the pedals.

No, don’t connect the TS splitter to TRS cables. Basically if the pedal’s expression input requires a TRS cable–for an expression input–then you should really only connect the 8 Step’s output to that one pedal. If the pedals’ expression inputs can also take CV–for example many, but not all, EHX pedals can take either CV or expression–then connect TS cables to the pedals’ CV/Exp inputs.

When the 8 Step is synced to MIDI Clock, with an expression pedal connected and controlling the 8 Step’s rate, the sweep of expression pedal’s range is the following:

Heel: 1/8x MIDI Clock Tempo
Toe: 24x MIDI Clock Tempo

As you move the expression pedal, the sweep increments in divisions of the MIDI Clock tempo.