Interesting site that you linked. I made a bookmark of it.The dating of the Revelation is not questionable.
According to the oldest tradition [in Iren., Adv. Haer. 5.30.3] Rev was written toward the end of the reign of Domitian (81-96). The book's own testimony indicates that it originated in the province of Asia in a time of severe oppression of Christians, which is most readily conceivable under Domitian. In the letters included in Rev, persecutions by the officials are expected (2:10), the blood of the martyrs has already flowed (2:13; 6:9), the whole of Christianity is threatened with a fearful danger (3:10): the immediate prospect is for the outbreak of a general persecution of Christians throughout the Roman Empire. In 17:6 John sees the harlot who is Babylon-Rome drunk on the blood of the saints and the blood of the witnesses of Jesus (cf. 6:10; 16:6; 18:24; 19:2). In 20:4 participation in the thousand-year reign is promised to the martyrs who have been beheaded because of their testimony for Jesus and for the word of God, and who have not worshiped the beast and his image and have not accepted his sign on their forehead and in their hand, i.e., those who have refused divine honors to the emperor (13:4, 12 ff; 14:9, 11; 16:2; 19:20). Christianity has collided with the state and with the state religion, the Christ cult with the imperial cult. In the interest of faith, Rev raises passionate objections to Rome and the imperial cult. That corresponds to the situation under Domitian.
Also favoring the end of the first century as the time of origin of Rev is the fact that according to 2:8-11, the church of Smyrna has been persevering for a long time, while according to Polycarp (Phil 11:3), at the time of Paul it did not even exist; and 3:17 describes the community of Laodicea as rich, while this city had been almost completely destroyed by an earthquake in A.D. 60/61.
taken from: The Book of Revelation
But, no, your late-dating of Revelation is questionable. But the proof for that is not found in the WCF, what they said or did not say. The real proof is in the Book of Revelation itself, that it was a vindication and encouragement for the saints of that age and a judgment against the enemies of God. And that enemy was not Imperial Rome, or some future Rome, but apostate Israel. Any unbiased reading of Revelation - providing the reader has a good backing in the OT and its connection with the New - should show that the historical judgment here was against covenant-breaking Israel.
There is also much here about future personal reward and punishment for saints and sinners, respectively, of all ages. But to miss the cardinal point that the bad guys here are apostate Israel of the first century leads to a whole domino line of error after error.
The Reformers, being hounded by the Romanists, naturally were quite to see Rome as the enemies here. Many Christians, whether or not they are convinced that Rome is the Beast, dont even think of seeing Revelation as referring to Israel.
But there is plenty of proof of this in Scripture. Maybe I should have started with this as the OP.