Yes, Rick:

When the Church is reaching out to the poor without including the gospel message; when faithful Seventh Day Adventists are shut out of ministry; when the Sabbath is disdained as legalism; when Jesuit meditation becomes mandatory for our leaders; when the demonic savagery of evolution replaces loving creationism in our schools; when acceptance and accommodation of homosexuality is taught by our "learned" professors; when ordained woman are baptizing openly gay lesbians married to other lesbians; when gay men's choirs perform to the acclamation of our congregations, yes, it is probably safe to say that the shaking has begun!

In the name of our Lord Jesus Christ, let the straight testimony go forth!

But where is the connection to the 144,000. Satan is putting much misdirection to cloud the truth...

I think you answered the question.
The shaking takes place within the church that professes to believe the three angels' messages.
And yes, the 144,000 are those left at the end.
But what do they do?

Don't forget the 4th angel of Rev. 18 -- who gives the third angel's message with added power.
That work of giving the last loud cry will be the work of the 144,000.
It is the work of those who remain in the truth of the third angel's message.

Reread the chapter of the "The shaking" it is after the shaking has shaken out the careless, that a group remains, a group that has triumphed -- They receive the outpouring of the Holy Spirit and "They moved in exact order, like a company of soldiers. .... I heard those clothed with the armor speak forth the truth with great power. It had effect."

Quoting Revelation 14:1-3 EGW writes
Why were they (the 144,000) so specially singled out? Because they had to stand with a wonderful truth right before the whole world, and receive their opposition, and while receiving this opposition they were to remember that they were sons and daughters of God, that they must have Christ formed within them the hope of glory (MS 13, 1888).

The 144,000 have a special work to do -- to stand with a wonderful truth right before the whole world, and it has an effect.

-- The 144,000 are those who believe in the three angels' messages, who go through the shifting/shaking time and remain faithful, even though the majority forsake the three angels message and make life difficult for those who cling to the message. Those faithful receive the latter rain and in its power give the last loud cry, a powerful last message to the world.

God's remnant must be cleansed and filled with the Holy Spirit before the loud cry will be given. Right now, multitudes in the church that professes to believe the three angel's messages, don't take those messages seriously, nor share them with others. The church now is filled with every wind of doctrine and cannot give a united "loud cry". All the chaff will be swept away in the great shaking, leaving the 144,000 to go with power to witness truth to the world.

They are the only ones who can sing the song of Moses and of the Lamb, for it is the song of their experience -- not only of their own personal salvation -- many others will sing of God's salvation as well, but Moses and the Lamb were willing to give everything for the salvation of others.
The 144,000, purified from sin and filled with the Holy Spirit, will risk everything to proclaim the last "loud cry" to world on the edge of eternity.



-- The great multitude are the ones that respond to the loud cry. They come from every tribe and nation, and out of Babylon, they too experience the great end time tribulation and wash their robes in the blood of the Lamb.



Quotes:

"... I heard voices which seemed to sound everywhere, "Come out of her, my people." . . . The glory of God rested upon the patient, waiting saints, and they fearlessly gave the last solemn warning, proclaiming the fall of Babylon and calling upon God's people to come out of her that they might escape her fearful doom. The light that was shed upon the waiting ones penetrated everywhere, and those in the churches who had any light, who had not heard and rejected the three messages, obeyed the call and left the fallen churches. {FLB 335}

"...The third angel's message is to lighten the earth with its glory; but only those who have withstood temptation in the strength of the Mighty One will be permitted to act a part in proclaiming it when it shall have swelled into the loud cry. {HS 155.3}

" I saw that God has honest children among the nominal (Millerite) Adventists and the fallen churches, and before the plagues shall be poured out, ministers and people will be called out from these churches and will gladly receive the truth. Satan knows this; and before the loud cry of the third angel is given, he raises an excitement in these religious bodies, that those who have rejected the truth may think that God is with them.--EW 261 (1858).

"Notwithstanding the spiritual darkness and alienation from God that exist in the churches which constitute Babylon, the great body of Christ's true followers are still to be found in their communion.--GC 390

The great work of the gospel is not to close with less manifestation of the power of God than marked its opening. The prophecies which were fulfilled in the outpouring of the former rain at the opening of the gospel, are again to be fulfilled in the latter rain at its close. . . . {LDE 203.1}

Servants of God, with their faces lighted up and shining with holy consecration, will hasten from place to place to proclaim the message from heaven. By thousands of voices, all over the earth, the warning will be given. Miracles will be wrought, the sick will be healed, and signs and wonders will follow the believers.--GC 611, 612

"There will be thousands converted to the truth in a day, who at the eleventh hour see and acknowledge the truth and the movements of the Spirit of God. "Behold, the days come, saith the Lord, that the plowman shall overtake the reaper, and the treader of grapes him that soweth seed" [Amos 9:13]. {1888 754.4}

So the 144,000 are represented by the angel of Rev. 18 that gives the loud cry calling God's people (the majority of whom are still in Babylon) to come out!
And while Babylon itself will react with fury and reject the message -- every honest follower of Christ will respond and come out and fully commit to Christ in faith and obedience to His law. A great multitude will respond.