1st person bailouts should become a feature, it would be a really nice adding for the immersion. Also i heard that it actually was a feature some time & updates ago? Anyone knows why it was taken out of the game? However i would really love this feature, if the player was able to look around while bailing & sitting in the parachute. Hope to see it someday in the game. Edit: Also, really nice flying. Loved the close call right before the initial crash, looked really cool.
This google drive link gives good information about your question regarding some planes. The chapter "III. Schießflug" of manual "Me 110G-2-4 Bedienungsvorschrift" describes which gun is fired by which button, at least for the Me110 G2 and G4. Not all manuals in this Google Drive state the button mechanism for each plane's guns, but it should answer your question in general, that some seperated triggers were used. Also the manuals are very interesting if you want to find out some more details about those planes. I hope that I could help you or someone else.😊