I only have two Made Marion NPCs who are intended to star in later games. Alvin will be a LI in Game 2 (set after MM) and Fawzia will be one in Game 3 (which is set earlier on the timeline than Made Marion, it's the story of the Nibirian uprising that ended the big war... so when we meet Fawzia she might be with the Game 3 protagonist who might actually be the King (gender-neutral) of Nibiru.)
The guards are unlikely to appear in any other games since they take place in different countries and these guys aren't in any position to travel before or after the events of MM. One more Game 3 love interest does appear in the Made Marion Mega-Guide (available for sale once we leave Early Access) and narrates Meissa's lore story.