Rotten Memory and Distorted Rabbit could alude to the fact that the protagonist has forgotten her crimes that she did long ago and are reminders of that.

The revenge enemy's are probably the anger that they manifest from both your baby and husband, since we killed then and all (this is prob the weakest reason for their names but thought to share it anyway)

Insane Cat might represent the protagonist in the crimes that she has committed.

Mask is probably the persona she unintentionally uses to hide the fact that she's a killer.

Laila's colors could represent Your dark soul, this one's a stretch but the name is normal so idk lol.

Fumetsu's heads could mean the two personality's you have (one insane and the other the persona).

Relviz could also represent the persona and is the opposite of Distorted Rabbit, a bright being that can do no wrong and could be how the others see you (normal).

The only one's I can't think of is old face, IDA and YBF. I think these guys are their own thing rather something that's tied to you, YBF is but for a different reason then everyone else.

That's it, I've have fun thinking about this and had fun too lol. Have a good one :)