Read the lore section in the main post Yea go for it. After the mod is released, you can do anything with it purely ingame excluding tampering with any of the files. More clarification will be made about this on release
No, only the cab and some engines are carried over. The chassis is WAY larger and weighs about 2 to 3 times more
If possible for the engine, it can be added, especially gasoline, such as the v10 9.3 and v8 8.0 engines
CTRL+h'd an entire jbeam file changing F to R. Resulted in pure hilarity such as "rlexbodies" and "RLT_MAX"
Fun fact, the school bus is a Gavril Durham, or at least what a bus version of Durham would look like. --- Post updated --- Gavril just wanted to make Durham in England, but that became a danger.