Question #1: Are there other earths with human life on them?
Bear with me a minute.
We know that Jesus Christ created everything.
Jhn 1:1
In the beginning was the Word, and the Word was with God, and the Word was God.
Jhn 1:2
The same was in the beginning with God.
Jhn 1:3
All things were made by him; and without him was not any thing made that was made.
We also have the creation account to consider.
Gen 1:1
In the beginning God created the heaven and the earth.
In the original Hebrew text, the word for heaven, šāmayim, is plural, and the word for earth, 'ereṣ, is singular. In other words, the Bible only speaks of one earth, and not of any other earths that you mentioned in your question.
Additionally, the word human means of or belonging to man.
https://symbolgenie.com/origin-of-the-word-human/
With this in mind, we need to recognize that the Bible calls Adam the first man.
1Co 15:45
And so it is written, The first man Adam was made a living soul; the last Adam was made a quickening spirit.
1Co 15:46
Howbeit that was not first which is spiritual, but that which is natural; and afterward that which is spiritual.
1Co 15:47
The first man is of the earth, earthy: the second man is the Lord from heaven.
1Co 15:48mea
As is the earthy, such are they also that are earthy: and as is the heavenly, such are they also that are heavenly.
1Co 15:49
And as we have borne the image of the earthy, we shall also bear the image of the heavenly.
Seeing how the word human means of or pertaining to man, and seeing how Adam was the first man, there could not have been any other men before him. Not only this, but this first man was of the earth, earthy, and, as I already noted, the Bible only speaks of one earth, and not of any other earths.
Furthermore, Jesus is not only called the last Adam, but he is also called the second man.
Since Jesus is the last Adam, no other Adams could have come after him.
It is important to note that the name Adam not only means man or human, but it is also etymologically linked to adamah which means ground or earth.
https://bibledictionarytoday.com/biblical-names/adam/
Finally, since Jesus is the second man, no other humans or men could have been created between the timeframe of Adam's creation and Christ's incarnation or else Jesus could not rightly be called the second man.
We all die in the first man or as a result of Adam's transgression, and we can all be made alive in the second man or in the last Adam.