Hey, I'd love to answer your questions but you need to submit them one at a time. I'll take your first question here. Then submit each other question separately. The contradictions you are referring to are really paradoxes. It is the Party's version of "doublethink" or accepting two seemingly contradictory terms at the same time.
"War is Peace". This is a paradox the party wishes to instil in the outer party in particular. While Oceania is at war, which they constantly are, there must be peace within the state. Only then can Oceania be truly strong to fight the war. Everybody must be on the same side, hence internal peace, for victory. This way the Party can remain in perpetual power.
"Ignorance is strength"- If people remain ignorant, they will not question the Party hence making the country "stronger".
"Freedom is slavery"- If people are free to do things and express ideas contrary to party doctrine, everybody is made weak. They are slaves to their own ideas and not strong under one idea from the Party.