In this case, you can choose either "is" or "be", but you should be consistent. There is only one verb "ensure", which is used for both clauses.
It would be more normal these days to use "is/are" with verbs like "ensure". The use of "be" is the subjunctive present form of "to be". It is formal. My writing style is quite formal and I would never use it. Modern American writers use the subjunctive more often than British writers but I am not sure if they would use it with "ensure".