How far do most Christians accept Plato's 'the Forms'? I asked a question on Plato's the Forms to Justin Welby (using films as an example of what might reflect God- after all, if Plato was correct, everything reflects something perfect and heavenly).
I got no response from him, but this was what his secretary wrote:

"I’m a bit rusty but recall that Plato considers that there is a perfect ’ heavenly’ model for everything we experience here.  A former Archbishop of Canterbury who was a New Testament theologian, Michael Ramsey, suggested something more startling.  He said, “God is like Christ and in him there is no un-Christ-like-ness at all”.  Does that not stand the platonic ideal on its head?

To expand that concept, it means that there is nothing hidden in the nature of the Almighty (whom we cannot see) which is different from the nature of Jesus as revealed or manifested to human beings.  There are lots of other hints here and now: our appreciation of beauty, the sense of awe which both attracts and repels (see Rudolph Otto on “The Idea of the Holy”) but nothing compares with God as one of us.  The opening words of St John’s Gospel and the Letter to the Hebrews are startling in their vision.  The first employs the Greek idea of ‘Word’ reaching fulfilment in Christ, and the second refers to the culmination in Christ of a preliminary series of revelations.  Very exciting."

Is this the general belief of Christians?
Aren't 'all things' met via Jesus (for instance, what pleasure counts as a 'Jesus' thing and what doesn't?)
Yours is a deep question, to be sure, and I certainly cannot answer it for Christians generally, but only for me personally.  If what you are asking, in essence, is


  Does everything which is beautiful, perfect, awe-inspiring, sui generis, masterful, the zenith, the epitome, the quintessence find its fulfillment, either directly or indirectly, in the triune God?, 


then my answer is yes, and I have a feeling a few hundred million Christians worldwide feel the same way. And how could it be otherwise?

Jesus, as the eternal Word of the eternally living God, spoke everything, literally everything, into existence (John 1:3). He fashioned the universe, including our solar system and planet Earth, in such a way that everything on earth, including all living creatures, both animal and human, could live and prosper under His beneficent care. 

Some have even suggested that the universe is anthropocentric by God's design. Not that human beings are necessarily the "center" of the universe in the sense that "man is the measure of all things (Protagoras, 485-410 BC), but that the universe is home to (perhaps) the only planet on which the physical beings created in God's image could flourish in mind and body, spirit and soul. 

Since all things were created by and for Jesus Christ in accordance with the eternal counsels of the Godhead before anything or anyone (including the angels) came into being, all things point to Him in some way. In other words, everything in our material world which can be named (and some which are not named) are metaphors, analogies, similes, allegories, parables, similitudes, parallels to or for some aspect of God the Father, Son, and Holy Spirit. 

God alone had and forever will have the ability to create. We His creatures, on the other hand, have only the ability to invent, and to do so only with tools which have been given us by an all-knowing God, who is all wise, all powerful, and who created us and sustains us by the word of His power. The human species does not possess anything that was not first given to it by God. 

I include this last paragraph because Plato believed, if memory serves, that a chair on earth, for example, has a form called "chairness" in heaven. The chair on earth may be well made, sturdy, attractive even, but the chair sui generis is a heavenly form. I for one do not agree with this, though I may be oversimplifying Plato's thought. (Feel free to correct me.)

In other words, as touching anything manmade or man-invented, there is not necessarily an eternal and perfect form in the heavens. Even the inanimate objects and the animate life-forms God created do not have corresponding forms in heaven, though they do, as I suggested earlier, correspond metaphorically to some aspect of God's eternal being. 

For example, the very notion of reproduction, whether of microorganisms, vegetation, animals, fish, or human beings speaks of God's inexhaustible supply of good things as reflected in the ability of all living things to be fruitful and multiply, according to their kind. The universe, we are told, is constantly expanding, and why not? God has no limits, and while the universe is neither infinite nor eternal (at least from the perspective of eternity "past," when all there was, was God), it certainly speaks of God's limitlessness or infinitude. All metaphors, of course, "break down" eventually, because they are, in a sense, only substitutes, as it were, for some aspect or attribute of God's eternal being.

God is love. God is a God of relationships. Within the Godhead are Father, Son, and Holy Spirit, each of whom love one another, share in the very same nature, and are in accord regarding their Plan for the Ages. Each may have a different role, as it were, but even then, when Jesus trod this earth there was nothing He did in which the Spirit and the Father did not also participate, each according to His role. For example, the Father directed the Son to do X; Jesus obediently did X; and He did so in the power of the Holy Spirit. 

At Jesus' baptism, we have a wonderful illustration of this cooperation within the Godhead. The Son enters into the waters of baptism (a metaphor, I suggest, for the baptism He would one day experience at the cross) so as to fulfill all righteousness (a theme I will not develop here). As He emerged from the water, praying, heaven opened; the Spirit in the form of a dove descended bodily and remained on Him; and a voice from heaven said, 


  "You are my well beloved Son; in You I am well pleased!" (conflation of Mt 3:16,17; Mk 1:9-11; Lk3:21,22; Jn 1:32-34). 


The very notion of love, as it is seen in the human species, may be a pale imitation at times of the Love of God, but it nevertheless reflects, albeit faintly at times, His love. 


  "Greater love hath no man than this: that a man lays down his life for his friend,"


Jesus said. He in fact did that very thing, but with a twist: He gave His life for the godless, the sinners, the unrighteous, His enemies (Rom 5:6 ff.).

In conclusion, I guess I would be most comfortable in saying that the best metaphors (and I use the word as a hypernym, of sorts, for all the words denoting similitude in one way or another) as emanating from the created order of things, via language and ideation, are related to the higher values and attributes of the human species, such as love, self-sacrifice, loyalty, beauty, wisdom ("Go to the ant, thou sluggard"--Proverbs), knowledge ("and Adam knew Eve . . ."), the use of giftedness for the greater good, inventiveness, awe, joy, peace, and many other such things, including, perhaps, irreducible complexity and the interrelatedness of all things under the sovereignty of Almighty God. 


  "For from him and through him and to him are all things. To him be the glory forever! Amen" (Romans 11:36 NIV).