You have to be more specific about your question, I don’t get what you’re trying to ask.
By “self-contained”, I meant that you can play P4 without having played the earlier games. Same thing with P3. P1 and P2 are more connected but let’s not talk about that. P3 is also connected to P4 in some ways but it hardly matters when you’re playing each individual game. It’s only of significance when you take into account of the spin-offs. For example, playing P3 and P4 first before playing the Arena spin-offs would be ideal so as to not spoil yourself beforehand.