Welcome and thank you for the detailed report. You are correct in #1 that this is most likely that your system requires some additional driver packages, if you knew what they were we could add them to this list for consideration as an optional addition at boot.
In regard to #2, you do not need graphics at all, and even during your error, your server was online at http://embassy.local, where you can do both install and initial setup. Following this you can continue to access from any client using LAN or Tor access, or client applications. The OS is designed first and foremost to be headless, so there is no need for a monitor, keyboard, mouse, etc either - you can tuck your server into a convenient corner - all it needs is ethernet and power!