That succulent is super tough, I don't know why they have died, I have a huge one, it gets sun all day, I water it every 7 days or more because sometimes I forget to water it, and every year it keeps growing, I guess I'm lucky with the mix.
About the mealybugs it is curious that I have not seen them on this plant in my garden, as soon as I have time I will check it and I will tell you if it also has mealy bugs, I suppose that the climate helps in the care of this succulent.
Oh yea.. they handle sun like champs! That's why this one is so red. I also water it about every week only.
I hope you don't find any :P