Scratch all of this I guess. I was reading another post about priest spells not affecting the priest that casts them. Then the poster replied back that IEMod was causing it. I just assumed that was how those spells worked! So on a whim, I started the game without IEMod and now my rites scrolls work fine. Sorry if I wasted anyone's time. I was not aware of these bugs with the mod.
That is what I was attempting to do. I had Aloth and Durance both standing beside my rogue, who had 10 mechanics. Each time either Aloth or Durance would attempt to use the scroll, they would say something like "blast", "curses", "no", etc. and the scroll did not affect the rogue's mechanics score on the character sheet when I checked afterward. Based on Aloth's and Durance's reactions, it appears that the scrolls were failing somehow even though they both have lore 10 and the scrolls only require lore 4. It also shows in the combat log "Aloth/Durance activates Rite of Hidden Wonders". I just now added 10 more of the scrolls and tried again and they continue to not work. I'm adding them with the command: additem rite_of_hidden_wonders_l2 10. The green text being the command, blue being the item to add, and red being the quantity. I got the item name from this thread: Reference list for items, talents, abilities, etc.
I eventually had to add some gloves with +mechanics to my inventory in order to disarm the trapped chest since the legitimately obtained mechanics scrolls that I started with don't appear to work. I'm in Endless Paths of Od Nua if that matters. I guess I'll try them outside somewhere to see if that has any effect.