I'm sorry I have to disagree with you on the fact that the Bible give us hardly any information on how to protect ourselves from demonic opression.
You even Quoted some of the way that we are able, If we choose to follow them, to protect ourselve by putting on the Full Armor of God found in Ephesians 6:10-20. We need to do this every day as Christians. There are also referance of God's protection and how we can aquire it in the old testement found in Psalms many times. Psalms 91, 23, 46..... Just look all though them and you will read of His strength, His angles that guard, and the trials that we will fall into at the hands of our enemy (Satan), and we can over come because God has given us his word and his plan.
This is Spiritual Warfare we are talking about. Do you really think God is going to leave us hanging with no protection, no instructions. I DON'T THINK SO.
And casting out demonds, is still done. You do it, I hope when you feel a spirt of oppression, when things aren't going right. When you are sick and can't get over it. This is not just when you have a cold, or I sorry to say even cancer. I'm talking adout the colds that last and cause you not to go to Church or the kid problem that keep you from Church, that could be a demonic spirt of oppresion that you can cast away from yourself fairly easlly "In the name of Jesus Christ in cast you out" Spirt of what ever you think the problem is. I suggest that you have two people at least to do this. It has to be Christians,(Belive Jesus died on the cross rose from the dead, and has taken thier sins away with his blood that he sheed on that cross.) to do this, but I have had it work when only one true beliver is there.
I have cast out demonds myself.(now I am praying, because Satan does not like others to hear this, so please pray for me to,) you don't do it yourself it is the Holy Spirt in you that does it. You can do nothing in youself it is though God and His Will. The moment you start doing iin the other way you are asking for trouble, Satan will take that and run and start useing it agianst you, even if you are a Christian.
Next thing, Christians can be possesed and hasseled be demonic forces.
it is what you allow in your life that allows that stuff in. I personally find it comforting that Satan feels he still needs to hassel me, if he didn't then he must be comfortadle where I am in life and I am not doing what I should be for Christ.
Angels and Fallen Angels, you and me have some things we agree on and some we don't. I'll just say what I think.
Angels where created by God as companions, and messangers, angel means messanger, Lucifer was God's second in comand, Lucifer decided he wanted to over throw God and rallied one third of the angels behind him, God threw them to the Earth, The reason I belive that the fallen angels are the demonds is that God is the only one who can create and some one would have to create the demonds, if they were not the angels Satan would have had to creat them and he can't, or God and I don't see that, or they are ghost and sorry there is no such thing as ghosts in that sence, people can't come back in that form.
The other Angels are very much still at work in people lives not just invisibly as guard childern or your home, but I know the reasure in visable ways also. Two of my sons have seen angels and I have seen then three times myself in desperet times in my life, I know there are other stories of them. Miricales still happen today, not only in unseen ways but in very visable ways.
And now if you can't tell I did have some dealing in the occult. I didn't get as far as alot of people did, but I do know enough to know to stay away from and what you are getting into when you start even with just simple things like role playing games ,D&D(Dungens and Dragons) or reading some herbal books and the power of nature, They seem OK on the outside, but on the inside demonic force lurk to atach them selves to you and the only way to escape is Jesus and Spiritual Warefare.
I hope most of this makes sence to you, I just wrote what I felt God wanted. Disorganized as it might be.