A. Still a world war - all over the place.
B. A key presumption but that's what diplomacy is for.
C. That's World War 3.
D. With the help of Japan it is possible but not easy.
A. No, it's a war between Britain and Germany/Italy. A World War involves a significant number of countries being involved, not just a widespread war.
B. German diplomacy. WW2. Right.
C. Do you really think USSR would sit it out while Germany was getting deeper and deeper involved elsewhere?
D. Why the Hell would Japan help out Germany in fighting in northwest Europe? I know Japan had some ambitious plans that didn't entirely meet up with reality, but sending a fleet to help Germany defeat Britain seems a little of a high-risk/low-benefit exercise for Japan. Sure, Germany would like it, but given Japan's interests, that's a touch unlikely.
In short, the changes necessary to achieve any of your suggestions transform the situation so much that it's not possible to have a meaningful discussion on them as they bear no resemblance to the situation as we know it. If there's a proposal that Japan will get involved in NW Europe, then all bets are off as one can invent anything one likes.
"We need oil and resources to continue our war with China. I know, lets sail our fleet to the other side of the world, and help our ally, who has oil and resource shortages of his own, in order to help him defeat another country in a place where there is no oil, leaving our own area of interests unguarded while our fleet is away." I mean, attacking the USA Pacific Fleet to stop it interfering in the SE Asia land grab was unwise enough, but at least one can follow the reasoning involved. This just comes down to: "Japan does whatever Germany wants it to do."