… The kernel panic is coming from VBoxSVGA …
Not so. Kernel panics (FreeBSD bug 254412) are very easily reproducible with VMSVGA.
Please set the guest to VBoxSVGA, and no more than one processor, before it boots.
… guest additions still not working …
Guest additions will not work properly with VMSVGA.
Please set the guest to VBoxSVGA.
Thanks