Nitakujibu according to Christian theology which i believe is the only true theology, why i believe it to be true is a topic for another day.
About Lucifer
Lucifer kama walivyo malaika wengine wote jukumu lao lilikuwa ni kumtumikia Mungu na kumwabudu tu. They were created to do only that. Doing anything rather than obeying ni uasi mkubwa. Hapakuwa na haja ya written laws to show that he did wrong.
Unlike humans, angels and other heavenly beings have no hope for second chances. This is because humans may fail due to lack of faith because sometimes we cannot feel or see what we are supposed to believe in. God gives second chances to human because there is a possibility for them to know him and choose him. But what about angels? they live with God and commune with him on a day to day basis, they don't need faith in their life because they see God and His majesty everyday. So if they choose to rebel there is nothing that can change their minds. ONCE THEY REBEL AGAINST GOD THERE IS NO TURNING BACK.
So the question of aliasi kwa sheria ipi au iliandikwa wapi jibu ni kwamba Sheria zipo kwa viumbe wenye imani ndogo,waliokuwa kiimani hawahitaji sheria ziwaongoze. Since angels live with God they don't even need imani coz they are sure of God presence and they know who He is and what He desires from His creation. According to christian theology hata leo tuliookoka hatuongozwi kwa sheria bali kwa imani.(If you are a learned Christian iam sure you understand it)
Regarding Death Penalty
Again i will refer to the Christian theology which clearly it seems you are not familiar with. According to Christians theology which is bolded with the birth, death and resurrection of Jesus Christ the only emphasis is on love and forgiveness. The Bible teaches to forgive and pray for other people so that they can turn from their sinful life styles and surely not killing them. Go and take a look at the New Testament of the Holy Bible and you will see what i am trying to say here.
About allowing the Devil to exist and therefore Sins to exist
When God created the universe, He wanted His most valued creation to worship him willingly. Worshipping willingly requires to choose God first. Choice requires freedom and also requires options to choose from. Sin happen when we do not obey God, having ability of not obeying that's what we call freedom. This all comes down to the doctrine of FREEWILL.
Having this ability to choose is what makes us human. If we didn't have this ability we would have been like robots who are just programmed to respond to certain commands. GOD didn't want that. He wanted to be worshiped willingly.
In all this keep in mind that He created everything and he has put a choice in front of us and he made it very clear where every choice leads. His choice is simple choose Him and spend eternity with Him in Heaven or deny Him and spend eternity away from Him in Hell. Just as your short few years on Earth can earn you everlasting life the same short life can leads to everlasting torment. The scale is only fair. We can choose to put a finger on fire but we can't choose not to get burned. WE CAN CHOOSE WHAT TO DO BUT WE CAN'T CHOOSE CONSEQUENCES OF OUR ACTIONS.
About God being all powerful (OMNIPOTENCE OF GOD)
God has many attributes one of them is being all powerful but also Has many other attributes. God's wisdom exceeds all wisdom of man or anything created for that matter. Sometimes being powerful is allowing your enemy to exist so that your people can be able to choose. Remember a choice to obey or not to obey was there before even the snake lied to Eve and then Adam. The Devil came and inspired them not to obey but the choice was always there.
One final issue is about Sin. God didn't create Sin as many of you thinks. Sin is a by product of not obeying. Lets take this example, God created food to be eaten by man, but not eating will result to starvation. He didn't create starvation but starvation is a result of not taking food.