It sounds like the problem was either with what fonts were installed or the
process you used to install them.
1) When you run the LaserWriter Font Utility, if the drive is recognized
and does format, then the drive is connected properly and operational.
2) No, you can't install screen fonts.
3) You will need the screen fonts on the workstation. Downloadable fonts
on the workstation are unnecessary, but do not harm anything.
4) There is no theoretical limit to the number of screen fonts you could
install in your System file, but you would eventually run out of RAM or
disk space. The limit of files per folder is 64,000.
5) The LaserWriter IINTX manual shows how to make the connections properly
and format the disk. If these processes work, the drive is operational.