I do the bass track first. It’s midi and I type it in with my keyboard, then quantitize to get it perfect. Then, when I record the guitar rhythm, I have both a bass and click to play along with.
When I’m using my airpods, I can only hear the actual acoustic sound from the instrument itself. That makes it more difficult for sure and has taken a lot of practice. When I’m able to use my headphones I can then monitor my instrument, which is easier.
Typically yes, singers are the last to be recorded (harmony vocals the very last). There are times when some overdubs are done after vocals but usually not. They can choose to hear everything as they record, yes, but I have been to lots of sessions where a singer will not want all tracks in their ears, so the engineer customizes a mix that helps them sing the best. Thanks for the questions!