And i heard there are planets swaps what does that mean?
All the crewmates are available, but you can only get each of them when the planet they reside in is in the current monthly planet swap.
Right now you can get Neila and the two robot companions from metris-3, Tyr from taun, Miles from silva, D from La'ard, Oliver from the scar, and Kuno from ovar. You'll have to wait for next months planet swap to get the rest, like.. Luna for La'ko, domoy for Ivan, Na'ja for Ivan's implant, and Dionysus for Issac's body.