With such a diverse book as the Bible (representing a wide swath of early Judaism and Christianity), there are no black-and-white generalizations that can be made for many matters. I believe that the Society's positions are not representative of those of the texts they cite, and they do not take into account the broader religious context that isolated verses in the NT presuppose.
1) only the Father is truly God
This is probably true for some texts, inasmuch as they refer to such a relationship between "Father" and "Son". But others that ascribe a higher christology to Jesus could fairly be treated as binitarian in their devotion to Jesus (which refer to Jesus in terms that in the OT would be reserved for God), and it certainly true that Jesus is called theos in some texts, including those use the term in a qualitative way (i.e. theos describes the nature of the Word in John 1:1 the same way that "love" describes the nature of "God" in 1 John 4:8.....everything that love is, God is / everything that God is, the Word is). The generalization that the Bible teaches that "only the Father is truly God" is therefore not accurate, tho it is true for some texts.
2) no immortal soul
Again, this is not so clearcut. Some texts assume no personal eschatology at all (beyond a ghostly existence in Sheol, as it is throughout much of the OT), as that was the conservative belief held by Sadducees (see Luke 20:27, Acts 23:8). Ecclesiastes 9 is frequently cited by the Society as evidence against there being an afterlife (which is NOT the same as whether there is an immortal soul), but it is equally evidence against there being a future resurrection ("Never again will they have a part in anything that happens under the sun," v. 6...the very next verse after the one that says that "the dead know nothing"). The Pharisees believed in a future resurrection, but did not believe in an immortal soul; rather, the "soul" was the complete living person that perishes at death but which will be restored in the resurrection. This view is also representative of some of the texts in the NT. But the Essenes also believed in the immortality of the soul (as can be seen in Josephus, the Dead Sea Scrolls, 1 Enoch, and other writings), and believed that the dead in spirit form reside either in a heavenly paradise or in "the chambers of the dead" in the intermediate state between death and resurrection. Other Jews, such as Philo of Alexandria and the author of Wisdom, were also directly influenced by the Hellenistic anthropology of the immortality of the soul, and these books were a direct influence on the NT. Thus, there are passages in the NT that reflect this anthropology: 2 Corinthians 5:1-9 (which refers to the body as temporary tent and death as a form of nakedness in which the person is "away from the body"), 2 Corinthians 12:2-4 (which allows for one going to heaven "out of the body"), Philippians 1:21-24 (which construes death as "departing to be with Christ" and life as "remaining in the body"), 2 Peter 1:13-15 (in which death involves a similar departure from "this tent of the body"), and Revelation 6:9-11 (which even uses the word psukhas "souls" to refer to the dead martyrs in their intermediate state between death and resurrection, who must wait in heaven until their number is complete). There are other passages like Luke 16:19-31 which depict the conscious existence of the dead in the period between death and resurrection. A single generalization of "what the Bible says" is therefore inadequate.
3) no hellfire
The same could be said here. Much of the OT was written before such a concept came into existence, and parts of the NT do not necessarily presume the apocalyptic tradition. The parts of the NT that do incorporate apocalyptic scenarios, on the other hand, construe of a final punishment in a fiery eschatological Gehenna after the resurrection. The clearest instance of this is Jude 6-7, which refers to those "suffering the punishment of eternal fire"; this passage, as well as v. 14-15, directly quote and allude to 1 Enoch (see here for a complete discussion), which has a very well-developed concept of Gehenna and punishment in eternal fire (see 1 Enoch 27:2-3, 100:4-9, 103:7-8; compare also 2 Enoch 10:1-4 on the connection between the sin of Sodom and eternal fire). This demonstrates that the wider body of literature is relevant for the usage of terms in the NT itself. The specific phrase "eternal fire" (puros aióniou) in Jude 6-7 was common in the period as a reference to the punitive fires following Judgment Day, and can be found in 4 Maccabees 12:12, Testament of Zebulon 10:3, 3 Baruch 4:16, etc. The apocalyptic material in Matthew also explicitly refer to the "eternal punishment" following Judgement Day and the fire of eschatological Gehenna (Matthew 5:29, 10:28, 23:33, 25:46). Other similar statements in Jewish literature of the time include 4 Ezra 7:32-38, 2 Baruch 59:10, 85:13, Apocalypse of Abraham 15:6-7, 31:2-6, etc. Revelation 20:10-15 has a version of the familiar apocalyptic scenario involving "torment day and night forever and ever" after final judgment. While individual texts could be interpreted in a way that denies a literal apocalyptic interpretation, the wider context which was formative for the NT references themselves shows that such a notion of hellfire is not absent in the Bible. But its presence also does not mean that the Bible as a whole presumes its existence.
4) restoration of God's original purpose for earth
The Watchtower teaching that God orginally intended for man to cultivate the rest of the earth to be like the garden of Eden is not found anywhere in the Bible. Nor is the description of paradisical New Jerusalem (which comes down to the earth) in Revelation 21-22 a description of an earth that has been entirely converted into a paradise.
5) Eternal life for the faithful
Again, "eternal life" is a concept found in some parts of the Bible, and not in others. Some passages that the Society quotes in favor of eternal life in a "paradise earth" (i.e. Isaiah 65:17-25) actually say the opposite. The many references to eternal life in John and in Paul do not presume an "earthly hope" of everlasting life.
