When Link first meets Marin in Link's Awakening, he mistakes her for Zelda. Zelda's sprite in this game is an edited version of Marin's. Given his departing the joint adventure by sail boat, this would explain his thinking or remembering Zelda's recent adventure with him and influencing what he sees in Link's Awakening.
In the intro for Oracle of Seasons, it's clearly bright daylight, while the intro for Oracle of Ages, it has more of a twilight-ish feel to it (observe). In the official timeline, Ages comes after Seasons, the intros to both games having hinted at that.
The core differences between both Oracle games are that Seasons is oriented around combat and exploration while Ages focuses more on puzzles and minigames. Both fit with the attributes of the goddesses Din and Nayru are named after — power in Din's case and wisdom in Nayru's. This also extends to the villains who capture both oracles. Onox uses brute strength to capture Din, protects his castle with a simple magical barrier that repels all entry, and fights Link one-on-one with a flail and then in his true form as a dragon. Meanwhile, Veran fights from the shadows using cunning, deceit, and manipulation to get what she wants, battles Link using magic attacks, and relies on a illusionary puzzle, rather than a basic barrier, to protect herself at the top of the Black Tower.
In Ages, the first dungeon, the Spirit's Grave, is located in the same location as the penultimate dungeon, the Ancient Tomb, but in the present rather than the past. It doesn't take a lot of imagination to suspect the two might be the same — the Spirit's Grave largely consists of looming, barren rooms, whose contents from the Ancient Tomb may have crumbled away or been ransacked in the intervening years. This also extends to the items you get from both dungeons: the Power Bracelet is just a less-powerful, time-tested future version of the much mightier Power Glove.
So wait a minute - Ralph is Ambi's descendant. Since Ambi's death in the past means Ralph's death in the present, this means that he isn't descended via a sibling or a niece/nephew, but via Ambi's child somehow. So... where did this child come from? Easy - when Ambi set sail to find her own lost lover, she either met someone else or got married off in the future. It's not impossible - maybe Ralph is descended from a political marriage.
Fridge Sadness: Canonically, the order is Seasons to Ages. This means Ambi never gets any closure.
). In the official timeline, Ages comes after Seasons, the intros to both games having hinted at that.