I think so, according to the manual:
"The sub-oscillator of the ES1 allows you to run an external channel strip signal through
the ES1 synthesizer engine, by using a side chain.
To process a channel strip signal through the ES1 synthesizer engine
1 Set the Sub knob to EXT.
2 Choose the side chain source channel strip from the Side Chain menu at the top of the
But Ski is right - you need to have something to trigger the ES1 in the first place. Try adding a region to the ES1 track with one note lasting for the length of the song. When you play that region, if you have the ES1 Mix fader fully set to the sub osc, you should just hear the sidechain input.
I'm not at Logic now to check, but I think thats how its done.
Same goes for the LFO too - if there is something in the region to trigger the ES1, the LFO will start modulating.
Hope that helps!