There are several 'e's I think.
اکبرِ شیدا Akbar e Sheyda. sometimes some combinations sound strange to some people, like Akbar Sheyda. So it depends on each person. most of the time we add an 'e' to ease pronouncing the words.
اون دانش آموزه That student . ه here represents the vowel e, and shows the noun is familiar to us. exactly like what 'the' do in English.
دانش آموزه she/he is a student . Here ه=e means است.
کتابِ سبز green book. e here shows that these words are separate words not a compound noun.
کتابِ علی Ali's book . the above definition is suitable for this one as well.