Is it possible to have a different sample offset (09xx command) on each note played at a position in the same track? Or does each not then need to be in it’s own one?
No, the effect-columns are not related to note-columns in the track. If you want to have several notes playing different portions of the sample using the sample-offset command, you are bound to pick a new track for this, or just chop up the samples and assign the samples to other notes if you want them to play in the same track.
I think the last option suits best as you would not need to copy complete track DSP chains to more tracks and punish your 3Ghz cpu for being too simple.
No you wouldn’t, you would put all the DSPs in an effects track 