Is it possible to do multitrack recording/sequencing on the xp-50 without having to use the performance mode ie. by only using the patch mode?? HOW?

You must use performance mode for multitrack sequencing. A "SINGLE" (key mode) performance is just like having 16 patches/instruments/band members at your disposal for orchestration and recording: a single, unique patch assigned to each of the 16 tracks/parts. See info in your other thread.