I think we can safely assume that, omitting forced choices, the first planet is Tatooine and the last planet is Korriban.
So it its Kashyyyk vs Manaan. Picking one, the other becomes the choice for the 3rd map, it it is only needed to decide which planet should be second.
-Dangers of Kashyyyk vs security of Manaan.
-A Mysterious Message from Senni Vek urging us to travel to Manaan
-Brother quest for Mission, suggesting Kashyyyk
-Find out what is wrong with Zaalbar on Kashyyyk
-Metagame: Jolee is on Kashyyyk
-Metagame: Jolee has quests on Manaan
Even if i dont care about the Wookee, nor about metagame, the second planet appears to be Kashyyyk. Consequently the 3rd planet is Manaan. For the resulting order of Tatooine, Kashyyyk, Manaan, Korriban.