You do ask the easy ones, don't you?
Of course you realize these questions give opinion answers we cannot prove.
I reordered them to fit my answers better.
I do not believe time is a thing. I believe it is the perception of change.
By that I mean things age and decay. Our perception of that decline is measured by such as an orbit around the sun, etc. All subjective concepts.
In eternity past and future there was no decay, sun or moon. Thus the perception of eternal now.
But, with that said, things do change in eternity. We don't just do the same things over and over, but nothing ages or dies. It will always be light, etc.
Is God inside or outside of time?
Since it is a perception, not a thing, it really is a moot question.
God does not decay, etc. But, again, since time is a perception, a moot question.
Will God destroy time as we know it in the new heavens?
Difficult question. Death and decay will be thrown into the Lake of Fire, so our perceptions will change. So, I guess you could say our perception of what we call time will be destroyed.
This is a very subjective question and answer.
These questions may hurt your brain...I know they do mine
Since we are trapped in a reality where all we experience contains death and decay, it is really beyond our ability to truly conceive.