As an example: Legacy>Jam pack1>Guitars>Delicate echoes. If I click on the channel strip's plug, I can only set Volume, release, Cutoff. Imagine I want to change the pitch bend range, how can I do ? Thank you very much (I know that these Legacy things can be found as well in the not-Legacy content, but the channel strips are sometimes different).

Hi - You can't access additional settings from that plug-in -- those Instruments with the very simple interface are GarageBand versions, which come with limited controls. However, as you noted, you should be able to find that Instrument in the regular Factory content: If you instantiate Sampler, you'll find that particular guitar instrument [used in Delicate Echoes] in the Factory folder as Clean Electric Guitar 1. If you then copy the effects plug-ins over from the other [Delicate Echoes] version, and set the appropriate controls in Sampler to match the settings there as well, you'll duplicate the sound. Then you'll be able to change the PitchBend Range in the Details panel in the SYNTH pane in the Sampler window [See the screenshot below].