will all the factions have phase jump?
because i don't find it logical that an alien race and humans will have exactly the same way to move in space. i don't think that the odds of something like that to happen are so good, and it will be a bit boring.
if you do different star drives to each faction you should do it something similar to sword of the stars every star drive has its advantages and disadvantages some are faster then other. one advantage that i think will be cool is to have one of the star drives to be able jump into every point they want in the gravity well only if they have explored it already but it should be slower then a different less accurate star drive. and i think if you add the possibility to stop one of the star drives mid way during the jump or something if you changed your mind and don't wanna jump there. and i think that if you do something like that it would give you more possibilities for the relics like the chance that a relic could be useless to one faction and might be a key object for other faction.
hope you like my idea