Isaiah 9:6 clearly states that it is His name - "
his name shall be called"
The word name is from the Hebrew word Shem meaning:
name
reputation, fame, glory
the Name (as designation of God)
memorial, monument
The rest of it is your understanding and I don't trust other translations. (Note: NIV translates as Everlasting Father, still ...)
When learning about God, keep in mind that He is God and not man. Numbers 23:19 In case you are learning about God as though he is a man, all your understanding will go wrong just like the Theory of Evolution

.
When it is written that His name is wonderful, then it is correct. His name is Mighty God, then certainly it is. His name can also be used to praise Him (Ps 96:2), remember He is God and not a man.
You quoted the name of Elijah, well, my name is Prashanth meaning peaceful in our regional language. It certainly does not mean that I am always a peaceful person. I am like everyone who can lose temper during stressful situations. No issues with the name of Elijah and I am not carried away if there were any insertions to force the understanding of the meaning of the name of Elijah. What matters to me is the name of God, in this discussion. His name is Prince of Peace and that's exactly what He was. For example, when Jesus was being scorned during His crucifixion, He prayed for their forgiveness. He is perfect exactly befitting His name.
God named Jacob as Israel (Genesis 32:28) meaning "God prevails". It is correct. (Rom 8:31, Rom 11:1,11)
God names Abram, Abraham(Gen 17:5) meaning "father of many nations" which is again correct. (Gal 3:28,29)
We humans name ourselves for a mere reference to one another. The way God names is different (Is 55:8).
You learn about God the way God wants you to learn about Him i.e. godly ways .. for ex. Numbers 23:19 and not the worldly ways.
When God says His name is called The Everlasting Father , AMEN.
John 1
1 In the beginning was the Word, and the Word was with God, and the Word was God.
3 All things were made by him; and without him was not any thing made that was made.
10 He was in the world, and the world was made by him, and the world knew him not.
12 But as many as received him, to them gave he power to become the sons of God, even to them that believe on his name:
All glory to God.