I'm new to this, but looking through the talent and powerstyle files, I've managed to fix all but one of the problems above. I'll detail my actions just in case I've made a mistake.
In thor.engb, I deleted the following block to fix the problems with Lightning Rod:
1366 require {
1367 cat = level ;
1368 level = %thor_p3_req ;
1369 }
I also reduced the maximum level of the skill from 15 to 10, in order to allow the maximum damage range of 45-49 to be reached (line 1320).
In storm.engb, I changed the skin numbers (skin = #) to match their intended corresponding outfits.
In ps_thor.engb and ps_storm.engb, I basically searched for all instances of "icon =" and updated the numbers to match the changed icons.