What if Hitler had not invaded Czechoslovakia in 1939?

To my knowledge, after he did this and with Munich broken, Britain's policy of appeasement headed by Chamberlain stopped. Does anyone disagree that if he had not invaded Czechoslovakia, broken the Munich Agreement, that he could make war with Poland without it escalating into a war with Britain and France? I think Poland would not have caved into German territorial demands, even with pressure from France and Britain. Also, would the Nazi-Soviet pact to divide Poland still necessary or would Germany annex all of Poland and Lithuania?

If no war was declared by France and Britain, would the war have been be delayed?

Would Japan have still invaded North Vietnam in 1940 if there was no Vichy France?