I mean, there's a psych tag, so...I wouldn't be surprised if at least one if not both of them died lol
Depends on how you define 'happy', maybe they'll just be serial killers on the run lol
You've got a strange understanding of what tags mean, lol.
1) The Psychological tag does not mean crazy or psychotic or tragic or anything like that? It's just "psychological", and is used for manga that deal significantly with the protagonists' mental states and feelings. Our MCs here having serious trauma that effects them is more than enough to earn the tag, and that does not imply anything about their future. Manga as different from each other as Berserk and Insomniacs After School have the Psychological tag.
2) Tags are not destiny. They're mostly made by the people who upload the manga, not the author or publisher, who tend to have much more generic tags like "sci-fi" or "drama" or "yuri" only, rather than in depth plot detail tags.