i decided to create my own p40 setup
Can you post that??
It is possible to have a SZ with a convoy marker to be adjacent to a Japanese territory and an UK territory at the same time.
Can both Japan and UK disrupt this convoy at that moment?
Yes.
If you can disrupt 2 convoys at a time, do Japan chose who to attack, does the allies or can they do both. eg SZ 1.
Since they happen on two different turns, they can do both.