Repeatable missions, and level scaling (separate questions)

[GamerXYZ]

I've decided to use Berobert's Nightmare Modules to make missions un-repeatable because repeatable missions constantly filling the mission list is so annoying. However, it's been a couple of years since I last played the game, so I forgot: are there any missions that MUST remain repeatable to succesfully play all missions once (assuming when never discarding necessary mission items, of course)? If a mission is only unnecessary to repeat if you play missions in a specific order, then include that mission as having to remain repeatable.

Also, is there an easier way to remove the repeatable flag from all missions simultaneously instead of using Nightmare Modules which has you go over the mission one by one? I'm going to guess not, but better to ask than to just assume it doesn't exist.

As for the level scaling question: I know Darthatron's AOI editor offers the option to set level scaling to use your highest level member, but is it possible to edit the hex values into a custom level scaling formula that takes the lowest level (or if lowest is not possible, then the average level) of your first 6 party members and ignoring any other party members?