By all means don't give up until it's over, but I don't see much hope with those 2 plants. You need to get rid of the mealy bugs (dead or alive) in order to know that they don't come back. The visual cue of a new bug would be lost in that white mass. Maybe use a spray bottle with a focused beam to shoot them out of there.
What kind of light are those plants receiving? How much water? Are there holes at the bottom of the pot? Is there anything about the history of the plants, like where you got them and how they were at the time of sale, which might shed light on the situation? I see 2 plants in there which might come out okay. Maybe review how you're caring for the whole pot in order to best ensure their survival. Bug infestations and rot are often cues to rethink potential care issues.
