Your source's definition of "Metatithimi" is incorrect. It does not mean simply to "transfer." It means to transpose, to change, or to swap one thing for another.
Note that of the other biblical uses of this word, none suggests movement:
Jude 4: For there are certain men, crept in unawares, who, before old old ordained to this condemnation: ungodling men turning ("transforming") the grace of our God into lasciviousness.
Galatians 1:6 I marvel that ye are so soon removed ("transformed") from him that calls you into the grace of Christ unto another gospel.
Hebrews 7:12 For the priesthood has been changed ("transformed"), there is made a necessity a change ("transformed") also of the law.
It's an understandable mistake the author makes. "Tithimi" means to lay, put, fix or establish. "Meta" means to change. So doesn't "Meta-Tithimi" mean to change where something is put?
Not really. "Tithimi" means "put" more in the sense of assigning a place to something. Meta-tithimi, then, means to change where something belongs, or, by extension, to change the status of something. That's why the word, "translate" was used in Latin, not "transfer," which would have meant what your author means.
Even as such, however, the bible doesn't make clear that Enoch lived forever. Although he was possibly somewhere other than a grave, he was certainly not in Heaven in the sense that he was standing before the beatific vision of the Risen Christ, for Christ had not yet been enthroned in Heaven.
The prevailing notion that Enoch was not in the grave comes from the Book of Enoch. The Catholic Church (and, following it, the Protestant churches) has not asserted that the Book of Enoch is necessary as a source of doctrine, so it is not in the Catholic or Protestant bibles (although it is, IIRC, in the Coptic bible). The bible, however, does quote from the Book of Enoch, in the Epistle of Jude:
"And Enoch also, the seventh from Adam, prophesied of these, saying, 'Behold, the Lord cometh with ten thousands of his saints, To execute judgment upon all, and to convince all that are ungodly among them of all their ungodly deeds which they have ungodly committed, and of all their hard [speeches] which ungodly sinners have spoken against him. These are murmurers, complainers, walking after their own lusts; and their mouth speaketh great swelling [words], having men's persons in admiration because of advantage.'"
It can. But it can also meant to transfer.
Note that of the other biblical uses of this word, none suggests movement:
You left out an important one:
Act 7:15 So Jacob went down into Egypt, and died, he, and our fathers,
Act 7:16 And were carried over (metatithemi) into Shechem, and laid in the sepulcher that Abraham bought for a sum of money of the sons of Hamor the father of Shechem.
This is the same word translated "translated" in Hebrews 11:5. Interestingly, it conveys probably exactly what happened. God carried over, took, Enochs body somewhere and buried it. He was not found.
I'd be the first to agree that anything about exactly what happened to him is speculation. Scripture says God took him, transposed him, translated him, whatever. But doesn't say where. I would agree though that he's not in "heaven", or doesn't have his final reward. I'm making the assumption that he's awaiting the return of Christ and will be resurrected at Christ's coming.