Lastly, the language dealing with "torment" evidently does not refer to literal pain or torture. The term is commonly utilized in a figurative manner throughout the book of Revelation (Rev. 11:10).
I do not know why you conclude that the torment in Rev 11:10 cannot refer to literal pain or torture. I admit that much of the affliction will evidently be on the spiritual level. But the two witnesses have power to send fire from their mouths (perhaps the idea is "power to send fire at their command") and consume their enemies. Their enemies will be killed in this way (Rev 11:5). They also have power to shut up heaven so that there is no rain upon the earth during the days of their prophecy, those days lasting three-and-a-half years. They have further authority to turn the water into blood. Additionally, they can smite the earth with every kind of plague as often as they wish (11:6). So the conclusion that the "torment" in Rev 11:10 is merely figurative seems quite likely to be incorrect.
I base part of this understanding on what the new BDAG says under the entry for BASANIZW: "of prophetic testimony as source of annoyance Rv 11:10.--9:5; 14:10; 20:10; GPt; Hv 3, 7, 6; s 6, 4, 1f; 4; 6, 5, 3f; 6" (Page 168). Furthermore, the context of Rev. 11:10 shows that the two prophets use their powers to kill and devour their enemies. How could such powerful feats literally torment all those who dwell upon the earth? It is more likely that the testimony of the witnesses serves as an annoyance [figuratively] for those who live upon the earth (Cf. C.H. Giblin, "Revelation 11:1-13: Its Form, Function and Contextual Integration." NTS 30 (1984) 433-59.)
What is interesting to me about the Rev 14:9-11 passage is that the text mentions the absence of rest after speaking of the smoke of their torment going up:
Rev. 14:11 and the smoke of their torment goeth up for ever and ever; and they have no rest day and night, they that worship the beast and his image, and whoso receiveth the mark of his name.
The text implies that the smoke of their torment goes up forever because they have no rest from their suffering day or night.
Well, the verse says that the smoke of their torment ascends forever. It does not say that the "smoke" results from their toil and suffering. And what is more, the pain inflicted on those worshiping the beast could be symbolic.