1st - that is a npc thing. every npc that has a force jump level can jump to wherever they want
2nd - that one i think its due to the fact that tavion is using a sith sword and that gives her the ability to regain health. that can be also found on Jedi Outcast on the last level: when you go through a beam of energy in the middle of the map you get invulnerable for a time. and the effects and graphics of that beam are the same as tavion's sith sword power.
3rd - i also noticed that too...you cant do that only they can (again, another npc thing...)
4rd - that case also repeats with the cultist commando ( a cultist that wields dual-pistols). they are there because they were leftovers that raven never introduced in the levels maybe they thought about doing so but they didn't. about the cultist destroyer funny thing: he uses a power that can suck force energy and then gets close to you, explodes and kills everything around him. you can spawn both these cultist on the console and see it by yourself.
hope that helped!