This book, including all its chapters, _____ interesting. The students as well as instructor ______ in agreement about it.

The correct option is "is, are".

Let us break down the grammatical rules for both sentences to understand why this option is correct.

First Sentence: "This book, including all its chapters, _____ interesting."
In English grammar, parenthetical expressions or prepositional phrases introduced by words/phrases like including, as well as, along with, or together with do not change the number of the subject.
Here, the true subject of the sentence is the singular noun "This book". The phrase "including all its chapters" is non-essential information set off by commas and does not make the subject plural.
Therefore, the subject requires a singular verb, which is "is".

Second Sentence: "The students as well as instructor ______ in agreement about it."
According to standard subject-verb agreement rules, when two subjects are joined by as well as, the verb agrees with the first subject mentioned.
In this sentence, the first subject is the plural noun "The students" (while the second subject "instructor" is singular).
Since the first subject is plural, it requires a plural verb, which is "are".

Combining these two rules, the correct verbs for the blanks are "is" and "are" respectively.