OK. Then you can program a switch so that one pitch block can do the octaves or the momentary 5th.
Cab block is very powerful for tone shaping on its own due to the channel strip section, which adds various mic/tape pre selections, drive and saturation.
Cab block also has high & low pass filters, proximity, and the channel strip has 2 band EQ. If you load a "null" or flat response IR, you can use all of the tone shapers in the cab block without the coloration of a mic'd cabinet, which is pretty cool on its own for emulating a bass DI into a console.
Preamps themselves are in the Amp block, and also in the Drive block (pedal preamps generally, but there's a tape machine preamp and Korg SDD 3000 delay preamp). Really, if you've never looked at the types of drives and amps available and the number of deep parameters you can adjust, it's worth digging into.
Do yourself a favor and RTFM and/or go on to the Fractal Audio Wiki page...and give yourself at least a few hours of free time to do so. There's a lot to digest.