Hi Marco,
Starting with your last question first,
3. In case of wanting to use a recorded dialogue line instead of a microphone, what is the best suitable sample prototype to use by replacing the Generic Source Live prototype, but being able to trigger it through the Kyma Control Keyboard?
In GenericSource, if you change Source from Live to RAM, it reads from the specified recording instead of from the live mic input (and continues to be triggered from the keyboard).
If you have a folder filled with recorded dialog snippets, then you could replace the GenericSource with the prototype called Multisample KBD (cmd+B to search for it). Set the Samples field to something like:
{'Recorded dialog folder:line1.aif' sampleFileNamesInSameFolder}
If you want the line to finish after you trigger it from the keyboard, leave the ReleaseTime at its default (long) value. Otherwise, if you would like it to release when you release the key, change it to something shorter like 1 s.
If you leave AutoLabel checked, then, in the VCS, the Index fader is labeled with the names of the files in the folder. You can right-click (shift-click) on the Index in the VCS to change that to a Selection from list or Radio buttons if you prefer.