The ways to say something is not necessary

Question

In the sentence I wrote, I am thinking what is the proper construction and tone to relate two clauses of which one is about necessity of something

1) Note that the teacher only prepares a list of words and he doesn’t need to provide the word definitions.

2) Note that the teacher only prepares a list of words and he is not needed to provide the word definitions.

3) Note that the teacher only prepares a list of words and he is not required to provide the word definitions.

4) Note that the teacher only prepares a list of words and he is not obliged to provide the word definitions.

5) Note that the teacher only prepares a list of words and it is not required that him to provide the word definitions.

6) Note that the teacher only prepares a list of words and it is not necessary to provide the word definitions.

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Answer 1

I'd go for either

Note that the teacher only prepares a list of words and he doesn’t need to provide the word definitions.

or

Note that the teacher only prepares a list of words and he is not obliged to provide the word definitions.

2) and 3) imply that somebody else will provide the word definitions in the end, without the teacher's help.

5) is grammatically incorrect, it should be

Note that the teacher only prepares a list of words and it is not required that he provides the word definitions.

which conveys the same meaning as 3.

In 6), the second clause looks like it is directed to the pupils, as in:

Note that the teacher only prepares a list of words. It is not necessary to provide the word definitions, you can just translate them straight away.

Answer 2

The teacher must provide only the list of words, not their definitions.