Here is the Partial answers for your questions:
1) Lord KALI Destroy all bad people when he appears:
There are many incarnations of the Supreme Being as stated in Srimad-Bhagavatam (1.3.26): “O brahmanas, the incarnations of the Lord are innumerable, like rivulets flowing from inexhaustible sources of water.” However, out of all the various incarnations of the Supreme, the Srimad-Bhagavatam (1.3.28) specifically states “krishnas tu bhagavan svayam,” which means that Lord Sri Krishna is the original Supreme Personality of God.
2) Will the good people live for 1,00,000 years as they will be part of a new Satya Yuga?
"Lord Kalki will appear in the home of the most eminent brahmana of Shambhala village, the great soul Vishnuyasha.” (Bhag.12.2.18)
The Mahabharatra (Vana Parva, 190.93-97) adds to the description of Lord Kalki’s appearance: "Impelled by time, a Brahmana named Kalki Vishnuyasha will be born. He will possess great energy, intelligence and prowess. He will be born at a village called Shambhala in a blessed Brahmana family. As soon as thought of, vehicles, weapons, warriors, and arms and armors will all be at his command. He will be the imperial sovereign, ever victorious by the strength of his virtue. He will restore order and peace in this world, overcrowded with creatures and contradictory in its laws. That effulgent and greatly intelligent Brahmana will destroy all things. He will be the destroyer of all and He will be the maker of a new Yuga [Satya-Yuga]. That twice-born one surrounded by the Brahmanas, will exterminate all the low and despicable mlecchas wherever they will be found." So it explains Kali will destroy all and if need he is going to create people again with out any sins (He will establish moral law in the form of the fourfold varnas, or the suitable organization of society in four classes. After that people will return to the path of righteousness)
3) Will all the current technologies like internet, planes & mobiles exist in the new Satya Yuga?
If Kali establish moral law and make suitable organization of society in four classes. After that people will return to the path of righteousness. I don't think so our current technologies like internet, planes & mobiles will not be exist, it's going to be a creating new Yuga again based on his rules, thoughts and needs.