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"Eostre: Saxon and Neo-Pagan goddess of fertility and springtime whom the holiday Easter was originally named after." (Gerina Dunwich, The Concise Lexicon of the Occult, New York: Citadel Press, 1990 p.54)
"EASTER: Bæde Temp. Rat. XV. derives the word from Eostre (Northumb. spelling Éastre), the name of a goddess whose festival was celebrated at the vernal equinox; her name...shows that she was originally the dawn-goddess." (The Oxford English Dictionary, 2nd ed. Oxford: Clarendon Press, 1989)
"Astarte: a Phoenician goddess of fertility and sexual love who corresponds to the Babylonian and Assyrian goddess Ishtar and who became identified with the Egyptian Isis, the Greek Aphrodite, and others." (Oxford Dictionary of English)
"Ishtar: ancient fertility deity, the most widely worshiped goddess in Babylonian and Assyrian religion. Ishtar was important as a mother goddess, goddess of love, and goddess of war. Her cult spread throughout W Asia, and she became identified with various other earth goddesses (see GREAT MOTHER OF THE GODS). Great Mother of the Gods: in ancient Middle Eastern religion (and later in Greece, Rome, and W Asia), mother goddess, the great symbol of the earth's fertility. As the creative force in nature, she was worshiped under many names, including ASTARTE (Syria), CERES (Rome), CYBELE (Phrygia), DEMETER (Greece), ISHTAR (Babylon), and ISIS (Egypt). The later forms of her cult involved the worship of a male deity (her son or lover, e.g., ADONIS, OSIRIS), whose death and resurrection symbolized the regenerative power of the earth." (www.encyclopedia.com)
"EASTER: Bæde Temp. Rat. XV. derives the word from Eostre (Northumb. spelling Éastre), the name of a goddess whose festival was celebrated at the vernal equinox; her name...shows that she was originally the dawn-goddess." (The Oxford English Dictionary, 2nd ed. Oxford: Clarendon Press, 1989)
"Astarte: a Phoenician goddess of fertility and sexual love who corresponds to the Babylonian and Assyrian goddess Ishtar and who became identified with the Egyptian Isis, the Greek Aphrodite, and others." (Oxford Dictionary of English)
"Ishtar: ancient fertility deity, the most widely worshiped goddess in Babylonian and Assyrian religion. Ishtar was important as a mother goddess, goddess of love, and goddess of war. Her cult spread throughout W Asia, and she became identified with various other earth goddesses (see GREAT MOTHER OF THE GODS). Great Mother of the Gods: in ancient Middle Eastern religion (and later in Greece, Rome, and W Asia), mother goddess, the great symbol of the earth's fertility. As the creative force in nature, she was worshiped under many names, including ASTARTE (Syria), CERES (Rome), CYBELE (Phrygia), DEMETER (Greece), ISHTAR (Babylon), and ISIS (Egypt). The later forms of her cult involved the worship of a male deity (her son or lover, e.g., ADONIS, OSIRIS), whose death and resurrection symbolized the regenerative power of the earth." (www.encyclopedia.com)
your second source doesn't actually prove that easter is named after a pagan goddess...it merely establishes that the medieval historian bede believed that easter was named after a pagan goddess...it turns out that bede is not an especially reliable source on this subject...he himself admits that he has never witnessed any practice of this religion which by his own account died out hundreds of years before his time...so bede's entire story is based on hearsay...the fact is that there is not a single primary source that attests to the existence of this pagan goddess...
your last two sources are revealing in that neither of them state that there is any connection between astarte or ishtar and easter...although they identify several other correspondences...