I tried renaming the ./config/xfce4 directory and then reinstalling. It seemed to reset something, as when I logged in the user for the first time after the reinstall, it gave me the following option again:
Welcome to the first start of the panel. Choose below which setup you want for the first startup
Migrate old config
Use default config
One empty panel
I had used the "Migrate old config" the first time which gave the original problem. This time I chose "Use default config" which now puts the menu bar at the top instead of at the bottom, but many of the menu options are still missing icons. In addition, the old xfce panel is still at the bottom.
Should also add that the first time I installed (using the Migrate old config), the desktop was just a plain black background, and then when renaming the ./config/xfce4 directory and reinstalling, then choosing the "Use default config", the background is now gray and with the xfce logo rather than any Vectorlinux logo, in case that provides a clue as to what might be happening.
Do you know of any other place where these settings might be able to be removed and reset?
In the meantime though, I've managed to solve the keyboard issue:
For running a Dvorak keyboard, when configuring XCONF during the setup, do NOT use the Auto (xorg with NO xorg.conf) option. Instead, can use the VXconf option, and then manually edit /etc/X11/xorg.conf and add
Option "XkbVariant" "dvorak" underneath the line that has the XkbLayout