You’re right that this rule is ambigious in this rule book. But to me the intention of the game makers is very clear. That shows not from this rule book, but from all rule books after this version. For example in the rule book from 1943 2nd, They state specifically that all strategic bombing raids take place first. This resolves any argument about who pays the IPC’s to the bank, the attacker or the defender! Since they solved this in the next rule book, i think it is quite obvious what they intended and tried to correct.
Specific Lightning Assault Question
So the first question is - can you use destroyers as transports for lightning assaults? It seems like you should be able to, but it’s kind of unclear.
The second scenario: We have a transport attacking one territory and then lightning assaulting to a different territory and are wondering if - on the second attack - we can bring in planes that did not participate in the first battle. And also if a battleship waiting in the harbor of the second attack can bombard for that second assault.