God cannot change His laws, his identity depends on His law. His Law is the foundation of the universe; in particular the Kingdom of God.
I have never heard of two prophesies holding back the return of Christ. An algorithm controlled by God determines when things happen; there are variables such as, as individuals do we go with God or do we go against Him, and The False Prophet's effectiveness will be variable according to the gullibility of the deceived. The fine detail is not know until it happens.
In the KJV summary for 2 Thess 2. the day of Christ is preceded by a great apostasy.
Men are not made to never die the first death, they are not made to die the second death either; men are able to be resurrected, presumably indefinitely. Eternal life requires men be transformed, the second death requires a different transformation; seemingly Gog becomes a plague of insects.
What is the law the people are under in the 1,000 years and in the new earth era that follows? (Spoiler, Is it the Re:21 set)
That is the 2nd prophecy. The two witnesses are 4 days into their 1260-day ministry when the 5th trump sounds. Satan cannot sit on any throne until they are dead. Satan and the Beast have control of Jerusalem and then on the day the two witnesses are resurrected the Beast is sent to the lake and Satan is in chains as described at the start of Re:20. That is followed by the resurrection of the ones who will join the living. That day is day1 of that 1,000-year reign.
There is one resurrection only, that is the 2nd birth. Nobody who has eaten from the tree of life in Eze:47 (Re:20:4 list) or in Re:21 (Re:20:5) ever die because nobody breaks any of the laws that were in place.
Ge:6:3:
And the LORD said,
My spirit shall not always strive with man,
for that he also is flesh:
yet his days shall be an hundred and twenty years.
De:34:7:
And Moses was an hundred and twenty years old when he died:
his eye was not dim,
nor his natural force abated.
1Co:15:22:
For as in Adam all die,
even so in Christ shall all be made alive.
Ge:5:5:
And all the days that Adam lived were nine hundred and thirty years:
and he died.
Ec:3:20:
All go unto one place;
all are of the dust,
and all turn to dust again.
Ec:12:7:
Then shall the dust return to the earth as it was:
and the spirit shall return unto God who gave it.
Ec:9:10:
Whatsoever thy hand findeth to do,
do it with thy might;
for there is no work,
nor device,
nor knowledge,
nor wisdom,
in the grave,
whither thou goest.
Heb:9:27:
And as it is appointed unto men once to die,
but after this the judgment:
The first prophecy (2Thess:2) is about false Christians spreading false doctrine in their vain attempt to destroy what the Bible actually promotes.
1Tm:1:10:
For whoremongers,
for them that defile themselves with mankind,
for menstealers,
for liars,
for perjured persons,
and if there be any other thing that is contrary to sound doctrine;
2Tm:4:3:
For the time will come when they will not endure sound doctrine;
but after their own lusts shall they heap to themselves teachers,
having itching ears;
