A few bits of rambling thoughts,
Would GB and USA really fall out I think you need to go back to the Venezuelan crisis of 1895 to change that.
Not sure that GB would fall out with AUS/NZ as they where keen on a Federal empire (compared to CAN/SA) so if you fight them you lose everything (or at least all the dominions, you may be able to hold colony's by force
).
No WNT probably just ends up with a massive USN, a big RN and a smaller (proportionally) IJN so WW2 in Pacific will be different. (and Japan my learn that it cant fight US and hope to win.
Why would GB break the balance of power in Europe ? by supporting Germany ? a right wing Gov will be working in GBs self interest not Germany/Italy (and is unlikely to get on well with its allies).
Would a ruthless GB take the DEI itself ?
JSB