What is the significance of Jesus quoting Daniel 7:13 before the Sanhedrin? Also how does that relate, if at all, to Rev. 1:7?
Its a fair question to ponder.
As for their relation, I think there is both a similarity and a stark difference in the two passages you mention that refer back to Dan 7:13.
Jesus' testimony to the Sanhedrin revealed a strong opposition from the high priest (who would ostensibly be in favor of the Son of Man coming and receiving dominion over all peoples, nations, and tongues). The high priest evidently was opposed to the threat to his own dominion and wasted little time reacting. John used the future tense in Rev 1:7 saying that all kindreds shall wail because of Him. Evidently, John says they also shall be opposed to losing their dominion (if the occurrence of their wailing is yet future). The similarity of opposition in both cases seems evident, and equally so is the difference in their respective abilities to react.
Stephen's testimony to the high priest in Acts 6&7 resulted in a strikingly similar reaction as that of the Sanhedrin to Jesus in Mark 14 (seeing that Stephen's testimony elicited anger to the point he was stoned). Stephen reminded them their fathers rejected Moses, saying, "Who made thee a ruler and a judge over us?" But the same did God send again to be a ruler and a deliverer. They rejected Moses the first time but God sent him back to be a ruler and deliverer over them anyway. "As your fathers did, so do ye" even though Moses had truly said to the fathers, A prophet shall the Lord your God raise up unto you of your brethren, like unto me; Him shall ye hear in all things whatsoever he shall say unto you. And it shall come to pass, that every soul, which will not hear that prophet, shall be destroyed from among the people. Stephen accused them of being the betrayers and murders of the Just One. However, they held their anger until he made reference to Psalm 110, seeing the Son of Man standing on the right hand of God, "The Lord shall send the rod of thy strength out of Zion, rule though in the midst of thine enemies." Then they finally snapped, stopped their ears, and ran upon him with one accord, casting him out of the city to stone him.
Stephen's testimony using Psalm 110 before the high priest, and Jesus' testimony citing Dan 7:13, both elicited extreme hatred and intolerance for the claims.
Like the thread you call to mind beginning in Dan 7:13, Psalm 110 has a similar weave through Acts and Revelation 2, 12, and 19.
I think in both cases the significance is in the claim of what the Messiah will do, and how people react to that. What are your thoughts?