1. Elizabeth s born around 2010.. apocalypse happens on Nov 27,2020 and that time Peter, Elizabeth and young "Noah" also u stays in the bunker so they will survive.. there s a shot when young Noah enters to bunker he will look at Elizabeth first.. so all r going to some time line and young Noah marries Elizabeth and gives birth to Charlotte (we do not know exactly which timeline). Later some one is taking that child (probably Adam or sic mundus team) and giving to H.G.thannus during 70s so during 1986 u can see Charlotte as a young.. same time line during 86 Peter also come to winden later they r getting married and gives birth to Elizabeth.. so this s a paradox.

2. Season 2 last episode Noah mentions as some one took his baby ..Adam promises he will save Noah's family . that's why he does whatever Adam asks . Finally he got to know Charlotte s his daughter and Adam betrayed him after finding the missed pages from claudia before she dies.. it's not clear after giving birth how Elizabeth went to 2052 and how young Noah becomes priest which will cover in season 3. Hope this information s fine

Stunning theories ... this series has already eaten my half brain... waiting for season 3 now

I’m sure Noah and Elizabeth are the parents of Charlotte

Yes they are... It's reaveled already