I like the strategy but what are the logistics?
Try this and see how it goes:
G1: Build five subs. Use two subs to take out the British destroyer by Canada. Use three subs to take out the destroyer by the UK. Ignore the battleship and cruiser by Scotland. Use your airforce to take out the rest of the British fleet that you can reach. The point is to sacrifice your airforce to keep your navy alive. You may even use your bomber with the three subs and take it as a hit if the destroyer hits you back. Then noncombat your battleship and cruiser into SZ 109 with your three subs. Place your new subs in SZ 112. This gives you 10 subs (if both of them by Canada survived), 1 battleship and 1 cruiser. The UK can most likely destroy any one of your fleets but there is no way they can destroy the other two. SZ 109 is more important to them since they got to take out that fleet in order to prevent you from convoy raiding 8 IPCs. The side benefit of them taking out your fleet in SZ 109 is that the Italian navy will not be destroyed and they can then quickly secure the med and earn their national objective. If UK attacks the Italians anyway then no problem since you now are convoy raiding them for 11 IPCs (assuming that both of your subs off Canada survived).
J1: Do not make any attacks that would get the USA involved in the war. Since the USA gets to declare war on you at the end of turn 3 and get their income bonus on that turn, you will be attacking the UK/ANZAC/USA on turn 3. Of course, you can still attack the Soviets with your infantry and massive airforce. Just make sure that airforce is in position by turn 3 to take out the DEI, Malaya, Hong Kong, the Phillipines and the British fleet (if they are still in the area) on turn 3.
I1: Either secure the med on turn 1 if your fleet survived or start rebuilding if it didn’t. You may have to save your money for one turn in order to build more naval units on turn 2. Also, take out as many friendly neutrals that you can as well as Southern France and Greece. Once all enemy destroyers are gone then you can build subs without fear of being attacked.
G2: Build 10 subs. By the end of turn 3, you want to have around 25 subs.
Remember, you goal isn’t so much to take out territories right away but to deny UK /ANZAC/USA IPCs by convoy raiding them. After the first 4 or 5 turns, you have to spend some money buying infantry to protect yourself from the Soviets.
I haven’t tried this, but it seems like it would be possible for Germany to take out the West Indies on turn 3 while Japan takes out Brazil, also on turn 3. All three of the Axis would have to coordinate this to pull it off. Then, on turn 4, Germany builds an airbase while some of the Japanese airforce lands on West Indies, allowing them to scramble if the USA attacks back. Perhaps Japan should also build a minor IC on Brazil to help dominate the Atlantic