If God is all knowing why did he create the Devil period? Makes no logical sense.
Everything God does is right whether we understand it or not! God created satan as a blameless angel but pride jacked him up and he wanted to be above God so he was degraded to a fallen angel (lucifer) while persuading a third of the angelic host to follow him but God brought Jesus to this world to deliver anyone born into this world who will receive His Son so they wont end up like satan or his followers.
Ezekiel 28:
14You were the anointed cherub that covers with overshadowing [wings], and I set you so. You were upon the holy mountain of God; you walked up and down in the midst of the stones of fire [like the paved work of gleaming sapphire stone upon which the God of Israel walked on Mount Sinai].
15You were blameless in your ways from the day you were created until iniquity and guilt were found in you.
Your right on the main points. However, the name of Lucifer is only used once in the Bible, as the name God gave to him only.
His identity changed after his fall. Now his names are devil, satan, unclean, dragon, etc. Studying this out makes me believe that Lucifer was one of the Arcangels. There were 3....Gabriel (Messenger), Michael (Warrior), and Lucifer (Covering Cherub). Lucifer was made with precious jewels and pipes for "manifesting" the "Glory" of God as God is invisible (Spirit) with no visible form (Now He is manifested in Jesus as the son "declares" Him). Lucifer was responsible for leading the heavenly host in praise, and worship unto God with music (hence the pipes). Walking in the midst of the stones of fire was something God did, so that tells me that the Spirit of God would "inhabit" Lucifer during these times of praise and worship.
He was extremely beautiful, and got lifted up with pride as he thought he should be in God's place because he was the "manifestation" of Glory in heaven during these times of praise and worship in Heaven. This tells me that even Angels have some semblance of free will as 1/3 of the angels followed the devil to earth in the fall. These were choices made by them. Lucifer was created blameless until he made a choice to be prideful and sin.
Have you ever wondered why the devil hates humanity so much? Well.....he lost his place to us.
We now worship God in
Spirit and in Truth. There is no more covering cherub in heaven leading the Heavenly Host in praise and Glory unto God. Oh the Angels still minister, and praise God in Heaven, but we as converts have taken the devils place of high and willful praise unto God from free will of our thankful hearts. God realized the downfall of beauty and pride, and how it can pervert, so in His wisdom, He Himself took on the form of lowly man (us). When you realize just how this all works together, you begin to understand the amazing Love he has for humanity.
I've Know of people seeing Angels during a worship service standing right next to the people with their arms raised and worshipping right along with the people of God. The Spirit of God has been poured out upon ALL flesh, and the Angels are here, as well as in Heaven. A woman said there were as many Angels or more as there were people in a church service she was in, when God opened her eyes to let her see. She said that when it was time for the Word of God to come forth (preaching), the Angels all went to the back of the building and stood at attention as honor and reverence to God's Word.
This is for edification to my brothers and sisters. No one else needs to comment on this as it's aimed strictly at them.