According to their own publications, they get their information through angels and through resurrected members of the "anointed" class.
Huh? I don't remember ever reading that.
The part about angels is actually "old light," but was actively taught in the past. Check out these quotations:
The actual burning or destruction by fire is done by the officers of the Lord that are invisible to human eyes, that is, the cherubim, seraphim and angels ; but it seems clear that the cherubim have charge over fire or that which destroys. These invisible ones the Lord uses to put in the hands of his “faithful servant” class, that is, the man clothed with linen, the fiery message from his Word, or judgments written, and which is to be used as directed. The resolutions adopted by conventions of God’s anointed people, booklets, magazines, and books published by them, contain the message of God’s truth and are from the Lord Jehovah and provided by him through Christ Jesus and his under-officers…The interpretation of prophecy, therefore, is not from man, but is from the Lord; and the Lord causes events to come to pass in fulfillment of the prophecy in due time.
Vindication I, (1931) p. 120.
Without a doubt the Lord uses his angels to cause the truth to be published in The Watchtower... Certainly God guides his covenant people by using the holy angels to convey his message to them.
The Watchtower , February 1, 1935 , p. 41.
Certain duties and kingdom interests have been committed by the Lord to his angels, which include the transmission of information to God's anointed people on the earth for their aid and comfort. Even though we cannot understand how the angels transmit this information, we know that they do it.
Preparation , (1933) pp. 36, 37.
The "new light" came along later:
New Light: “Those who make up the one true Christian organization today do not have angelic revelations or divine inspiration. But they do have the inspired Holy Scriptures, which contain revelations of God’s thinking and will.”
Jehovah’s Witnesses – Proclaimers of God’s Kingdom (1993) p. 708.
In light of their prior statements, though, I have to wonder whether it was angels who conveyed the "new light" that they weren't receiving angelic revelations...
Now, as far as communications from the dead, they once believed that Pastor Russell was still running the work on earth from heaven after he died:
This verse (Revelation 8:3) shows that, though Pastor Russell has passed beyond the veil, he is still managing every feature of the harvest work. We hold that he supervises, by the Lord's arrangement, the work yet to be done.
The Finished Mystery (1917) pp. 144, 256
Hence our dear Pastor, now in glory, is without doubt, manifesting a keen interest in the harvest work, and is permitted by the Lord to exercise some strong influence thereupon.
Watchtower Reprints , November 1, 1917 p. 6161.
Because Judge Rutherford was unhappy with all the devotion to Pastor Russell among the Bible Students, he came up with some "new light":
New Light: “No one of the temple company would be so foolish as to conclude that some brother (or brethren) at one time amongst them, and who has died and gone to heaven, is now instructing the saints on earth and directing them as to their work.”
Jehovah (1934) p. 191.
However, despite the above "new light," the Watchtower's current teaching is nearly identical. They still teach that anointed ones who have dies and are in heaven are communicating information to the remnant here on earth for publication:
It is fitting, then, that one of the 24 elders, representing anointed ones already in heaven, should stir John's thinking. (Revelation 7:13,14a) Yes, that elder could locate the answer and give it to John. This suggests that resurrected ones of the 24-elders group may be involved in the communicating of divine truths today. Revelation - Its Grand climax At Hand! (rev. 2006) p. 125.