[b]Here my take on regeneration, true faith, justification, and imputed righteousness:[/b]
Regeneration is a washing/purification brought by the influence of the Spirit of Truth (the truth shall set you free), so one has a new heart, or is "born again" and old things have past, and all things are made new. This new heart is a faithful heart, a faithful heart is one that has both repented and believed.
Faith consists in both repenting and believing, neither of which are external works, but consist in the internal condition of the heart, both repenting and believing are acts of faith which are done by the heart. Believing and repenting are changes of the heart, not some mere changes of outward conduct.
Upon this condition (of true faith), we access the grace that is in Christ. So we are justified by grace through true faith.
Imputed righteousness is a covering over all of our repented sins, it is the forgiveness of all past sins that have been turned away from, so that we are not punished at all for our repented sins, but are forgive of all our repented sins.
Regeneration and the new birth consist in the sinner repenting (turning from sin) and believing (trusting in Christ) as he is lead by the Spirit to do. Repenting and believing is what regeneration/conversion/the new birth consists of.
Regeneration/conversion consist in a sinner yeilding to the Spirit of Truth, thus he is purified and washed by the Spirit, which results in the sinner having a new heart, being born again, being a new creature, having true faith, having repented and believed from the heart, whereby God forgives him of all past sins.
And so nobody is saved until they obey the gospel, which requires them to repent and believe from their heart.