Also something that came up in the other thread. Ellen White apparently grants Satan omnipresence, having him in two places at once during the Investigative judgment.
In Early Writings Ellen White says Satan is in the heavenly holy place busy answering the prayers of those Christians who rejected Miller's "heavenly" message about Jesus coming in 1843.
Early Writings:
Then a cloudy chariot, with wheels like flaming fire, surrounded by angels, came to where Jesus was. He stepped into the chariot and was borne to the holiest, where the Father sat. There I beheld Jesus, a great High Priest, standing before the Father. On the hem of His garment was a bell and a pomegranate, a bell and a pomegranate. Those who rose up with Jesus would send up their faith to Him in the holiest, and pray, "My Father, give us Thy Spirit." Then Jesus would breathe upon them the Holy Ghost. In that breath was light, power, and much love, joy, and peace. [56]
I turned to look at the company who were still bowed before the throne; they did not know that Jesus had left it. Satan appeared to be by the throne, trying to carry on the work of God. I saw them look up to the throne, and pray, "Father, give us Thy Spirit." Satan would then breathe upon them an unholy influence; in it there was light and much power, but no sweet love, joy, and peace. Satan's object was to keep them deceived and to draw back and deceive God's children
And
And by rejecting the two former messages, they have so darkened their understanding that they can see no light in the third angel's message, which shows the way into the most holy place. I saw that as the Jews crucified Jesus, so the nominal churches had crucified these messages, and therefore they have no knowledge of the way into the most holy, and they cannot be benefited by the intercession of Jesus there. Like the Jews, who offered their useless sacrifices, they offer up their useless prayers to the apartment which Jesus has left; and Satan, pleased with the deception, assumes a religious character, and leads the minds of these professed Christians to himself, working with his power, his signs and lying wonders, to fasten them in his snare.
And in Great Controversy Satan is simultaneously in the Most Holy Place accusing the professed followers of God in the investigative judgment:
Great Controversy:
While Jesus is pleading for the subjects of His grace, Satan accuses them before God as transgressors. The great deceiver has sought to lead them into skepticism, to cause them to lose confidence in God, to separate themselves from His love, and to break His law. Now he points to the record of their lives, to the defects of character, the unlikeness to Christ, which has dishonored their Redeemer, to all the sins that he has tempted them to commit, and because of these he claims them as his subjects.
This is all a bit strange, because while Satan is the accuser of the bretheren, and did famously accuse Job, etc. Revelation 12 shows us that Satan was cast out of heaven following Jesus' ascension. But Ellen White has him in the heavenly Holy Place AND the Most Holy Place--at the same time.
Revelation 12:3 And another sign appeared in heaven: behold, a great, fiery red dragon having seven heads and ten horns, and seven diadems on his heads. 4 His tail drew a third of the stars of heaven and threw them to the earth. And the dragon stood before the woman who was ready to give birth, to devour her Child as soon as it was born. 5 She bore a male Child who was to rule all nations with a rod of iron. And her Child was caught up to God and His throne. 6 Then the woman fled into the wilderness, where she has a place prepared by God, that they should feed her there one thousand two hundred and sixty days.
7 And war broke out in heaven: Michael and his angels fought with the dragon; and the dragon and his angels fought, 8 but they [
a]did not prevail, nor was a place found for [
b]them in heaven any longer. 9 So the great dragon was cast out, that serpent of old, called the Devil and Satan, who deceives the whole world; he was cast to the earth, and his angels were cast out with him.
10 Then I heard a loud voice saying in heaven, “Now salvation, and strength, and the kingdom of our God, and the power of His Christ have come, for the accuser of our brethren, who accused them before our God day and night, has been cast down. 11 And they overcame him by the blood of the Lamb and by the word of their testimony, and they did not love their lives to the death. 12 Therefore rejoice, O heavens, and you who dwell in them! Woe to the inhabitants of the earth and the sea! For the devil has come down to you, having great wrath, because he knows that he has a short time.”
13 Now when the dragon saw that he had been cast to the earth, he persecuted the woman who gave birth to the male
Child. 14 But the woman was given two wings of a great eagle, that she might fly into the wilderness to her place, where she is nourished for a time and times and half a time, from the presence of the serpent.
Given the timing of the birth of the child, etc. this appears to be a different struggle than when Jesus in the gospels referenced seeing satan fall like lightning from heaven.