Thank you so much for compiling that list! The meeting/romance/marriage between Celeborn and Galadriel will be an early event in Season 4. In our version of the story, he is an elf of Doriath, and he is 'currently' in the north with Círdan at the end of Season 3. So, we will need them to meet (and marry) early in Season 4, likely by the Feast of Reuniting. Certainly before Finrod visits her in Doriath in 50-52.
Likewise, we have no intention of depicting the Athrabeth on screen, but we *do* want to show the (failed) romance between Aegnor and Andreth. For that reason, it is very important that all Noldor marriages/births happen well before that time, so it looks as though Aegnor is very much justified in his decision. The only exception we are allowed is Aredhel, because her marriage should seem unnatural for all sorts of reasons.
This should not pose too much of a problem - Orodreth was born in Valinor, regardless of whether he's Angrod's son or younger brother. Celebrimbor and Idril are likewise already born before the sun rises. What matters will be the birth of Gil-galad (regardless of whose kid he is) and the birth of Finduilas (again, regardless of whether or not she has a brother or where her father falls on the family tree). Even if there is a Sindar mother involved, the fact that the father is a prince of the Noldor makes the situation completely analogous to Aegnor. If Gil-galad is born *after* we show Aegnor reject Andreth...we'll have problems. And the 'sending him to the Havens' storyline works best if he's young when he goes. The real issue here is that Tolkien never really integrated Gil-galad into the stories of the First Age, so he doesn't fit. But he has to be born before his parents die off! So, yeah, 'birth of Gil-galad' will likely need to be placed somewhere in this timeframe.
Likewise, we have no intention of depicting the Athrabeth on screen, but we *do* want to show the (failed) romance between Aegnor and Andreth. For that reason, it is very important that all Noldor marriages/births happen well before that time, so it looks as though Aegnor is very much justified in his decision. The only exception we are allowed is Aredhel, because her marriage should seem unnatural for all sorts of reasons.
This should not pose too much of a problem - Orodreth was born in Valinor, regardless of whether he's Angrod's son or younger brother. Celebrimbor and Idril are likewise already born before the sun rises. What matters will be the birth of Gil-galad (regardless of whose kid he is) and the birth of Finduilas (again, regardless of whether or not she has a brother or where her father falls on the family tree). Even if there is a Sindar mother involved, the fact that the father is a prince of the Noldor makes the situation completely analogous to Aegnor. If Gil-galad is born *after* we show Aegnor reject Andreth...we'll have problems. And the 'sending him to the Havens' storyline works best if he's young when he goes. The real issue here is that Tolkien never really integrated Gil-galad into the stories of the First Age, so he doesn't fit. But he has to be born before his parents die off! So, yeah, 'birth of Gil-galad' will likely need to be placed somewhere in this timeframe.