Hello Milee777,
You've asked good questions. May I ask what have you read that deals with this? I would suggest
this book which will answer your questions, and it is free. You can get
a hard copy here. Either way I highly recommend you to read it.
As to your question about "all" being brought to repentance, it is concerning context of that passage that we must consider. The text is 2 Peter 3:9. Note this from verse 1
"To those who have obtained a faith of equal standing with ours..." We see this then is talking to and speaking of those whom God has saved.
The "all" in that passage is those to whom Peter addresses therefore it refers to those whom he has elected. God is patiently awaiting the sending of the Lord Jesus Christ again only until each elect person he has chosen to save comes to full repentance. That is the meaning of the "all" or the "usward" in 2 Peter 3:9. Read it, see that the context there is his chosen from the very beginning of the epistle to the end, the "you" the "all" the "usward" (worded according to whichever version you're looking at) is referring to the elect.
This passage shows us why God is patient, he is patient to bring into Christ all he has chosen before the sending of his Son.
Concerning being a vessel of wrath, and your question note that even his elect were formerly under wrath, like the rest of mankind, Ephesians 2:3; Note also Ephesians 1:4-11 for context of whom Paul is addressing in the Epistle. Place your faith in the Lord Jesus Christ, in his work on the cross, repent and believe his Gospel for the salvation he bought. If you have been brought to repentance and faith you need not fear his wrath, there is no condemnation in Christ Jesus; Romans 8:1.
God bless you Milee777.