I fucking love parallels! And theories.
The 100 delinquents are sent down to earth from the Ark to see if it is inhabitable. The Sky people are are met by the grounders who doesn’t want them there, who by nightblood, survived the radioactivity. Then we have the Mountain men, living in the mountains, prisoners in their own home because their bodies can’t handle the radioactivity. Also the people left on the Ark trying to figure out how to get down to the earth.
Someone sends down (a 100?) prisoners to the earth to see if it’s inhabitable, basically the new Sky people. They are met by Clarke and her nightbloods, who survived Praimfaya because of their nightblood, basically the new grounders. Then we have everyone in the Doomsday bunker, prisoners in their bunker because of debris from Praimfaya, the new mountain men. Also Bellamy, Raven and co trying to get back down to the earth.