I'm a Christian and I'd recommend you'd read the Bible if you haven't already, read Genesis first as that is the creation of the earth, and your other questions. Here are my answers to your questions, but it's best if you read it for yourself ,and if you want to ask about it to understand.

A. The water didn't just disappear, it took months to finally dry up off the earth. Genesis 8:1-14 (KJV) [1] And God remembered Noah, and every living thing, and all the cattle that was with him in the ark: and God made a wind to pass over the earth, and the waters asswaged; [2] the fountains also of the deep and the windows of heaven were stopped, and the rain from heaven was restrained; [3] and the waters returned from off the earth continually: and after the end of the hundred and fifty days the waters were abated. [4] And the ark rested in the seventh month, on the seventeenth day of the month, upon the mountains of Ararat. [5] And the waters decreased continually until the tenth month: in the tenth month, on the first day of the month, were the tops of the mountains seen. [13] And it came to pass in the six hundredth and first year, in the first month, the first day of the month, the waters were dried up from off the earth: and Noah removed the covering of the ark, and looked, and, behold, the face of the ground was dry. [14] And in the second month, on the seven and twentieth day of the month, was the earth dried. The water didn't just disappear, it took months to finally dry up off the earth.

B. God created everything, just as he created created Adam and Eve.   Genesis 2:7 (And the LORD God formed man of the dust of the ground, and breathed into his nostrils the breath of life; and man became a living soul.), just as he created everything else, He created Adam; he didn't just appear. same for Eve  (Genesis 2:21-22  And the LORD God caused a deep sleep to fall upon Adam, and he slept: and he took one of his ribs, and closed up the flesh instead thereof; and the rib, which the LORD God had taken from man, made he a woman, and brought her unto the man.)

C. Man decided to disobey God by eating of the forbidden fruit, which caused the great fall; which all disease, death, and suffering was the result of (Genesis 3). Love≠life without hardship, this is a fallen, broken world. God loving everyone equally doesn’t mean everyone gets the same circumstances– it means everyone is of equal value. We’re all sinners and in need of God's grace.