Firstly, a few things you need to know about enotes. Enotes rules stipulate that you only ask one question in the questions that you post. Multiple questions are not allowed. For us as editors we need to edit such multiple questions to only focus on one. This is what I have done so please do not ask multiple questions again.
At the end of this chapter, Winston tells us what the Party would need to do to be ultimately victorious. Having both committed themselves to continuing this highly illicit and dangerous affair, Winston realises that they are not necessarily committed to staying alive, but they are definitely committed above all to staying human:
But if the object was not to stay alive but to stay human, what difference did it ultimately make? They could not alter your feelings: for the matter you could not alter them yourself, even if you wanted to. They could lay bare in the utmost detail everything that you had done or said or thought; but the inner heart, whose workings were mysterious even to yourself, remained impregnable.
Thus it is when the Party shows that the inner heart is not "impregnable" by conquering the feelings of Winston, as shown in the tragic and moving ending, when they turn the love that Winston and Julia have into hatred of each other, that the Party shows that it is ultimately strong.