Pete, I agree with your doctrinal statement except for your ‘kept saved forever’ statement. I believe scripture teaches us we CAN be kept saved forever, but just as God does not force himself on man to become saved, in the same manner, he does not force man to remain saved.
Paul writes to Timothy this;
1 Timothy 4:1 (KJV) Now the Spirit speaketh expressly, that in the latter times some shall depart from the faith, giving heed to seducing spirits, and doctrines of devils; Man can choose to depart from the faith (which I see no other explanation other than they are/were saved) or choose to remain faithful. In summary, Scriptures teach us both eternal security (God keeps us so no outside entity can take our faith away) AND free will (we choose to accept and cling to Christ, and also to forsake and let him go). We are wise to understand both.
If we go ahead and assume that it is possible for us to relinquish our salvation through an act of our free will this then creates a logical problem.
The state of the world as it is was created by Man saying that he would rather follow Man’s will than follow God's Will. Because Man was made lesser than God, Man is incapable, because he was not designed that way, to do the job that God has which is to do what is best for God's creation and what is best for us. Man lacks the ability to see perfectly the consequences of his actions. This is why God's Will must be in charge.
Any "work" that Man does to attain or keep his own salvation therefore recommits the sin that caused the break between God and Man.
The only "work" that you can do, and that is a necessary exercise of your free will is to "believe in Him whom He sent".
28Then they said to Him, “What shall we do, that we may work the works of God?”
29Jesus answered and said to them, “This is the work of God, that you believe in Him whom He sent.”
John 6:28-29
After you have done that you are no longer in charge of maintaining your salvation. If you were in charge of maintaining your salvation you would fail. We would all fail. Maintaining our salvation by constantly repressing our free will and our desire to do according to our own will is a "work" outside of the requirement that Jesus described.
God's Will must be in charge. After we accept our salvation, it is.
Agreed, however, if we are sealed by the Holy Spirit until the day of redemption as Paul sated in Ephesians 4:30 (I too believe this is true for the born again), in that same verse we are warned to not grieve the Holy Spirit. I guess the real question is, how does one do that? We do know what Jesus himself said in Matthew 12:31.
It’s not about forcing anyone to remain saved, it’s about fundamentally transforming one’s nature from spiritually dead, to spiritually alive. It’s about becoming a new creation, the old is gone away. And just as one cannot earn salvation by works, one cannot un-earn it by works either. There are only two paths for those who are truly born again and turn away- either they are brought back (prodigal son style) or they’re taken home. Lastly though, just because someone walks an aisle or makes a profession of faith doesn’t make them born again. That is ultimately between that person and God. All I know is that once you’re born again, you are sealed by the Holy Spirit until the day of Redemption.