Roland S-1 and Digitakt

Can I use the Digitakt to control the Compact S-1 Tweak Synth from Roland?
Or to put it another way. Can I also use the effects of the Compact S-1 Tweak Synth to influence the Digitakt sound?

no.

source: S-1: Can the S-1 internal effects be applied to an audio device that is connected to the MIX IN jack? – Roland Corporation

by midi, yes.