1:New Covenant
The Torah doesn't speak of the new covenant because it is fundamentally the exposition of the old covenant (and the various laws particular to the jewish people such as the levitical code), the covenant had just been given to the jewish people, it was sort of necessary to work on the relevant covenant in the then and now. Not to mention the new covenant was not revealed to moses (the old covenant was).
That said however the old covenant is anticipatory, it looks forward to the new covenant and thus the new covenant is prefigured in its actions. Thus we see Christs sacrifice prefigured in the passover and at Yom Kippur, with both anticipating the final, eternal and expiatory sacrifice of Christ. Also I might like to add the Tanakh however does deal with the new covenant (Jeremias 31:31) in which God promised to Israel the fulfilment of the old law to its completion. Ergo God in his time revealed the existence of the future new covenant to the prophets.
As to failing to see it, rather its the jews through obstinancy that is common to mankind that fail to see the directional focus of the old covenant, and fail to see its fulfillment in Christ the saviour.
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2:The trinity
The whole idea is somewhat confusing, which is to be expected considering God is incomprehensible to us puny mortals

. However what I can say is that the trinity is not some idea of three gods (like mormonism). Rather its the belief that the one God ultimately subsists in three hypostases who mutually indwell, are co-substantial and co-eternal, with the hypostases interacting in perfect love through an everlasting and harmonious communion. Furthermore it is fallacious to say that each hypostases is distinct from another, The Father cannot be separated from the son and so forth. They are not "parts" of God. Also on another note one view has said that God could not have loved apart from the trinity, for from the harmonious communion between the hypostases the benevolence of God which moved Him to create is generated, a thing which would be absent in a monarchic God as in judaism. This being because God is complete in his perfection, and thus a monarchic God would have no need or necessity for love for God is complete. In the trinity God generates love through the communion of the persons, which then manifests in the desire to create in order to share that love.
addendum: Also I recall you have a panentheistic view of God where human beings are within God (you used a finger metaphor). How then is this different then having a multiplicity of personages withing God? Afterall each human being has a single personage and thus to say they are within God means that tacitly your saying that the single God has a plural nature, even more so than the christian view of the self-contained trinity.
3: Jesus as Messiah
That would be according to jewish sources

thats hardly an objective basis of inquiry. Now of course if you look as scripture as the foundation from which ones determination on Christ as the messiah is formed you have a differentiation of opinion, with well established arguments for either case. Since such arguments are well established, would take up a lot of time and be beating on a very dead horse (in consideration of history) I do wish to go through them all here (especially since they are generically christian and since it is 1 in the morning my time atm

)
As to why we say he is God the Son, second person of the trinity, the messiah and the saviour of mankind. Thats quite simple, because we believe he is and because that revelation has been passed down in the deposit of faith from Christ and the apostles.
As to lieing now that is simply a pointless attack. Furthermore it is simply a foolish and ignorant dismissal of an opponents point by arguing that it simply isn't true. Hate to break it to you, but just because you say something is false (or a lie) doesn't mean it is.