As far as the figures go, ou have to remember that they were aboard an aircraft carrier in the middle of the Pacific ocean! And as the B-25 Mitchell bomber was considered at that time as a low to medium altittude bomber, the flight crews were not often expected to were the heavier high altitude clothing of their B-17 and B-24 brothers. Also, naval aviators infrequently were the heavier clothing as well, unless they were going to be doing some high altitude flying, they usually didn't fly higher than about 10-12,000 feet.
For the bomb cart, if you can find an old Monogram SBD Dauntless kit, it has one that is fairly ok to use, especially if your going to place under an aircraft where no one can get a really good look at it!!