I believe that Lincoln had some information about 'an important girl'.
Rather I think Lincoln had a dream (or vision) where he saw that girl - and draw a picture.
About Maid:
I do NOT see any possible timeline right now - how Madi could be Octavia's child!
Well time travel cause massive problems - as ONE person CAN be twice (or multiple) time exists in SAME time & SAME place.
Madi is born like 6 years before The.100 comes down - where would be (or go) 'mother Octavia'?
WELL - Madi said in s07e01 this "I know what it's like to lose a mom", this means Madi saw how her mother died (or at least went away with NO return). This answers my own question where would 'mother Octavia' go!
Further - the scary face of Octavia in the season 7 promo (might be from s07e2) when Octavia realize a dead body with a similar face (as Aurora Black) in the octacon-helmet - could this be a strong hint some persons really could be in different time & different place(?)
Sure - Madi is a natural nightblood therefore HER mother is-was a nightblood too! (simple logic - I know the nighblood gen is recessive and might jump a generation), Therefore there are now multiple female candidates to be Madi's mother! The same is true for Madi's father - Lincoln had red blood, as we know from torture scene of season 1.