for blue you need at least a yellow blonde with no orange, i would do a strand test and see where bleach could get you, that way you can test before you damage all the hair with bleach you may not be able to get light enough for blue if the hair is stained
A medium or dark blue need hair as dark as a gold blonde.
Since used a color remover strongly suggest rinse the hair out thoroughly at least twice and wash the hair at least once. If this is not done color molecules that were shrunk will be left behind on the hair. Color molecules left behind when bleach is applied will re-oxidize and according to many previous posts in this forum the color removed will come back. So thoroughly rinsing and washing the hair after using a color remover can help prevent the color removed from returning if bleaching is done after using a color remover.
These are my suggestions and opinion.