As far as the nut goes, some advise as I work with a few nuts.
Watch out for the WD-40 or any spray as it can get under the paint and lift the paint dependending on the paint job. Had a friend who sprayed some WD-40 on his '68 Charger and it actually discolored his paint. Had a 2 tone gold Charger.
As far as removal, the safest bet is to get the correct tool. I wonder if current Dodge dealerships have this tool?
As far as removal without the special tool, when I was at Acura, I used to removel the antenna nuts with a pair of needle nose pliers opened just enough so that the tips fit into the recesses on the nut. If you have needle nose Vice-Grips, you might be able to adjust it to open just enpugh to get in the recesses. This might be a wee bit safer.
***** Special caution has to be used with this meathod or any tool removal method to cover the surrounding area with card board/cloth incase the tool slips as it may damage the paint around the nut.
Don't ask me how I know this....