Morning Bionic,
It would probably be worth removing the majority of any lime that is left. Easy-to-grow shrubs that could go in the hole include lavender, forsythia,peony,flowering currant,viburnum and cistus.
Fortunately camellias do well in containers so long as you use an ericaceous compost. One thing that I have learnt (too my cost!) is that they should not be placed where they get the early morning sun. Because they flower early in the year, temperatures are often low. Sunshine in the morning warms the flowers too quickly and they will drop off before they have fully opened. Other than that, they seem to be fairly trouble free. What a lovely present!