Didn't have any takers on this one, and perhaps its a dead issue. The national religion (aka SBC) for the most part agrees with "eternal security." But there are some deeper issues here.

For He says to Moses, "I will have mercy on whomever I will have mercy, and I will have compassion on whomever I will have compassion." So then it is not of him who wills, nor of him who runs, but of God who shows mercy.
Romans 9:15, 16

If Pharaoh could not resist God's hardening, can a sinner resist God's mercy? Who's really in charge?
Psalm 115:3 says

But our God is in heaven;
He does whatever He pleases.

Isaiah 14:27 says

For the LORD of hosts has purposed,
And who will annul it?
His hand is stretched out,
And who will turn it back?

Daniel 4:35 says

All the inhabitants of the earth are reputed as nothing;
He does according to His will in the army of heaven
And among the inhabitants of the earth.
No one can restrain His hand
Or say to Him, "What have You done?"

If we remember Paul's words in Ephesians 2, that we are dead in trespasses and sins, then Ezekiel's Valley of Dry Bones (Ezekiel 37) reveals a lot. The bones were not given a choice. If the Lord causes breath to enter them, they shall live. We are as dead as the bones. If God would have mercy on us, then we will have mercy.

Indeed, Acts 13:48 tells us

Now when the Gentiles heard this, they were glad and glorified the word of the Lord. And as many as had been appointed to eternal life believed.

Continuing with Ephesians 2

But God, who is rich in mercy, because of His great love with which He loved us, even when we were dead in trespasses, made us alive together with Christ (by grace you have been saved), and raised us up together, and made us sit together in the heavenly places in Christ Jesus, that in the ages to come He might show the exceeding riches of His grace in His kindness toward us in Christ Jesus.
Ephesians 2:4-7

For a look at foreknowledge vs. predestination, see this post.

Question #5: Can anything challenge God's grace?