The Interactive Phrase Synthesizer (hereafter abbreviated IPS) is not a sound synth, instead each of the two available IPS synths (A and B) allows you to model new music from existing, create one finger accompaniments, generate complicated arpeggios and more.
Cubase VST's MIDI Mixer window allows you to control MIDI devices for other functions than the regular sequencing ones. It works as a regular mixer for MIDI instruments (controlling volume, mute, pan etc), but it can also work as an editor panel for various instruments, effect devices etc.
Cubase VST comes with a number of VST Plug-in effects included. This chapter describes the included effects parameters. For general details about how to assign and set up effects, see the chapter installing and using VST plug-ins in the getting into the details document.