#2 is slightly more serious…but it would require a 4/4 shuck from Japan…and hence little or no real thrust against Russia or Africa…and even then USA will have a healthy production advantage in North America. USA could still base some bombers in UK or dump some units into Africa while deadzoning W Canada.
A mere 4x4 is not enough. Take into account, however, Japan will score 60s in a few turns, a 4x4, after settled, is going to cost only 24-30 IPCs. In this scenario is obvious Japan will have a half of starting fleet to defend against bombers. The other half of fleet can be used for Africa
Again, Japan needs more than a 4x4. I think the need is a 5x5, using also Manchurian IC units, and a IC at Alaska to send 14 or 15 units each round. The key is doing enough quick to ensure USA has to spend the full 40 IPCs is going to have after losing Pacific NOs plus ala and haw. Japan should spend 40-45 IPCs against USA in this scenario (maybe a bit of SBR against WUSA), that means 15-20 IPCs each round against USSR and Africa
Speed is key. If the strat goes right, it’s 60-70 IPCs from west axis plus 15-20 from Japan against USSR + UK mid game (they not should sum more than 60), and 40 vs 40 Japan vs USA. Of course, you can do the old JTDTM and is probable it works if you do quick. Both cases need a quick game with Japan, but Polar Express has the virtue that, if done many games right, can force allies to not ignore Japan, and I think is good for axis dictate the path of the game and not the allies
For the OP, if you combine a GUARD strat with Polar Express, west allies will have to spend time to kill german subs and also the italian fleet (and they are at distant places from each other). And time is all Japan needs to ensure both Polar Express or JTDTM
Edit: I guess in IJS you don’t buy any UK IC in India. In case you buy it, it’s not a full IJS, and the maths differ as well jap strat: a early India crush is way to go, but I’d still annoy Alaska with trading attacks