I hope you realize that God is here speaking to the Exiles and that he is promising them that after 70 years in Babylon he will bring them back to Israel. In the meantime he devises a "plan" for them to build homes, get on the good side of the city where he sent them, have children and live in peace.
This is not the plan (of salvation) Christians are talking about.
You know, you have done this before. You ask a question and it gets answered and then you change your original question. For example, you asked:
Where does God say "I have a reason, a purpose and a plan and you are part of it"?
I gave you the scripture passage from Jeremiah that spoke to that, but it's not acceptable because you say it was speaking to only certain people - ignoring the point that God does not only give the promise for one time only and he is no a respecter of persons, meaning he does not show favoritism towards anyone. So now you are asking for where scripture says God has a "plan for salvation"? I could give you hundreds, but tell me, do you want OT or NT, because it's in both. How many would satisfy your request? Would Paul be acceptable or is Jesus the only goto guy? I would like to know before I start feeling like that cat toy again. :o)