Where you are going wrong is that you are seeing regeneration as identical to justification.

Hi again. I haven't made an issue of that. Justification is a part of regeneration. What I am making an issue of is that the Bible says that in believing we have life:

"But these are written, that ye might believe that Jesus is the Christ, the Son of God; and that believing ye might have life through his name." John 20:31

It is just that simple! According to the Bible, we believe, we have life. Those that are dead hear the voice of the Son of God, and those who hear live.

The Lord opens our heart,
We repent and trust in Christ,
We are justified by God.

I agree. But when do we receive the life? What does it mean to die with Christ, be baptised into his death, and to be raised up with him into newness of life? What is the quickening which makes us alive from being dead in trespasses and sins if not the being raised with Christ through faith in the operation of God?

Being dead means not having life in your spirit. it means not knowing or being able to know God and his Son Jesus Christ.

But no one believes for salvation until the Lord gives him life (John 6:44).

The verse does not say that. No verse says that. It says that all that the Father gives to Christ will be drawn to Christ. And then they will come to Him. And what happens to somebody when the COME to Christ the Lord???? What happens if they don't come to Him?

"And ye will not come to me, that YE MAY HAVE LIFE." John 5:40

So the drawing cannot be life-giving regeneration, because the life is given when a person has come. Remember, we must look at all the scriptures!

You are equating the Lord opening someone's heart to hear the gospel, with regeneration. That cannot be, since the scripture, as well as saying that life comes with believing, also says that regeneration comes by the gospel, the word of God. Regeneration is not given to open somebody's heart to the gospel, but comes as a result of the gospel itself. We "purify our souls in obeying the truth, being born again by the Word of God." The heart is not purified until we believe, as the apostle Peter, who knew Jesus and was called of him to be an apostle, testifies in the Book of Acts.

You are reading into the words "whose heart the Lord openened," a word that is not there - namely regeneration. Cornelius was a man who was devout, and feared God, but he did not receive the Holy Spirit until the Word was preached. His good deeds came up before God as a memorial, and God sent him an angel to tell him to go to somebody who could tell him the words whereby he could be saved. What does it mean to be saved? Ephesians 2:5 - to be made alive!
Hope this helps