I tried to look this up, but we all know searching for anything on Tumblr is a travesty; Do we or will we know the ages and the way the other contestants have died/ got to the underworld?
Yes!
Since you knew Cecil in life, you know how old they were when they died and the sparknotes version of their death (in fact, if you want to find that out right now, read below the cut).
For the others, you may have noticed that in their character descriptions I say "Apparent Age: XX." You can tell roughly how old characters look, but you don't know their ages unless they tell you or you find out some other way. Same goes for their deaths.
I've also mentioned before that MC has the option to remember their death or not. This same option is extended to each person who dies. Characters may tell you that they remember their death, that they don't remember, or what their deaths were, but they don't always tell the truth...
Also, in some cases, characters who don't remember their deaths may not even know how old they lived to be (spoiler: this is the case with one - and only one - of the ROs).
It's possible to find out the truth for each RO and the other main characters, but in some cases, the truth is something you have to dig for.
