Maybe start by checking the fuseable links, usually mounted on the fender between the battery and the firewall. This may help Reatta Owners Journal - Ground Terminals & Junction Box Location
Maybe the transmission shift modulator has an internal vacuum leak? it would cause hard shifting too. Usually some transmission fluid gets sucked up by the vacuum thru the shift modulator and gets burned in the engine. Might check the tranny fluid level.
Try this link on the ROJ, lots of good information there
Reatta Owners Journal - Parking Lamp Assembly Removal
Reatta Owners Journal - Headlight Assembly Removal
It looks like the connector on yours is mounted right below the light socket, whereas on my car the connector is mounted farther down and to the right of the hood insulation.
I would guess the CRT needs replacement. Sounds like the vertical circuit has gone out, which would cause the CRT to display all the data in a horizontal line.
If you are handy, you can try to fix the broken lever. Back when I had my convertible, I found my lever was broke too. I sandwiched some brackets to each side of it and JB welded it all together.