Found a way to change your player model for cut sceens, not sure if it's been posted before, sorry I don't have the time to look through this whole post.
In the extdata folder with all the .npc files there is one called player.npc in it it has a line "playermodel player" all you have to do is change the 'player' to any model that you have in the base folder. For eg: playermodel ep1_obi and it will change your character in the cut sceens.
also just though I'd mention with changing character skins/models in SP all you have to do is change a line in the .npc file for the character you want to change. For eg: If you wanted to change Luke for quigon. put the quigon.pk3 into the base folder, extract the luke.npc and open it with notepad. The first line in the luke.npc file is playermodel luke all you have to do is change 'luke' to read 'quigon' (playermodel quigoin) pack the luke.npc file back up and pop it into your base folder. Luke will now be quigon.