Do you think there is something God doesn't know?
Regeneration is by God's grace alone, ordained by Him from before the foundation of the world.
Trinitarian faith in Jesus Christ is not a requirement for salvation; it is an outward sign of it. We are saved by the merciful grace of God through Christ's redemptive sacrifice, and nothing in ourselves.
"And you hath he quickened, who were dead in trespasses and sins;Wherein in time past ye walked according to the course of this world, according to the prince of the power of the air, the spirit that now worketh in the children of disobedience:
Among whom also we all had our conversation in times past in the lusts of our flesh, fulfilling the desires of the flesh and of the mind; and were by nature the children of wrath, even as others.
But God, who is rich in mercy, for his great love wherewith he loved us,
Even when we were dead in sins, hath quickened us together with Christ, (by grace ye are saved;)
And hath raised us up together, and made us sit together in heavenly places in Christ Jesus:
That in the ages to come he might shew the exceeding riches of his grace in his kindness toward us through Christ Jesus.
For by grace are ye saved through faith; and that not of yourselves: it is the gift of God:
Not of works, lest any man should boast.
For we are his workmanship, created in Christ Jesus unto good works, which God hath before ordained that we should walk in them." -- Ephesians 2:1-10.
That doesn't answer my question as to why bother with creating, dead in sin, those that He knows will be regenerated?