what does this symbol mean?

[rav]

https://imgur.com/a/oNoDXHk

[Padds]

its basically nothing in DD2
it means "locked in" in DD1 because of the way characters stayed around you would see so many positive and negative quirks that some would be replaced , this system was added so you could go to the sanatorium and lock in good quirks you wanted to keep, negative quirks became locked in over time and then would cost a lot to more to cure.

the transient nature of the roguelite characters in dd2 means your really unlikely to see that many quirks, and you cant pay to lock them in, nor do they cost more to cure once locked so it really doesnt do anything here

[a small rabbit]

It means its a rare Quirk. It's explained in the tutorial section under quirks.