I found 2 more spell combinations that will definitely work and 2 others that have a chance of succeeding. I've seen Power of Night, which is a 4th level spell given twice from the Ore Cart and so I think you should be able to get up to 4th level spells from it.
These first two are fairly easy fights:
Evil Book (level 3 spell so should be given by Ore Cart, although I haven't seen it yet) @level 2 cast twice makes both Elven and Human Shelter fights pretty easy. You can also get your Poison Skull to level 2 if you need it to help out your 2 books, although that is a total of 47 Mana. You need 1 point in concentration, 2 points in Chaos and 1 point in Meditation will really help with your Mana. Try to get as close to 40 Mana as you can so that you don't have to wait very long to cast your second book.
Demon Portal (level 4 spell so I think there is a possibility of it showing up in the Ore Cart unless it is excluded in the criteria somehow) @level 1 cast twice (you need 1 point in Concentration, 2 points in Meditation, and 1 point in Chaos so that you have at least 39 Mana and on round 2 you'll get +1 and have exactly 20 Mana so you can perform another cast) and you can fairly easily defeat both Elven and Human Shelter stacks (note that twice @level 1 is better than once at level 2 for this spell).
These next two are pretty dicey, but they have a shot at working:
Ball of Lightning (I have gotten this from the Ore Cart so I'm going to try this game and see if I can do it for real). You need to get this spell to level 2 and so that means 1 point in Meditation and 2 Points in Order. I had two points in Concentration in my test and so I think you're going to need to be level 5 so that you can get Concentration to level 2. The Human stack is very easy with this spell, but the Elven stack is really hard. The trick here is only use level 2 of this spell if you need to (for example, the Fauns are killed with a level 1 Ball of Lightning). You should have just enough and I think you need to be Daert Level 5 do the Elven stack. Mana is very important here, level 1 Ball of Lightning is 8 Mana and level 2 is 14. I had 42 Mana in my experiment, which allowed 3 casts @level 2 and I also had Concentration level 2. This might not be doable in reality and I used every point of Mana on the Elven stack.
Avenger (level 2 spell, but Order so cannot get it from Clarissa so must get it in the Ore Cart). You need to get this spell to Level 2 so that means you should put 1 point in Meditation and 2 points into Order. You should then have 1 point in Concentration so that you'll be at least able to cast it twice over the course of the fight. I also had Time Shift in my experiment, but I don't think you can get Distortion level 1 and Concentration, but it can be used to inexpensively extend Avenger if you need to so this might also work. Note that the Human stack is a lot easier than the Elven stack and so you should take out the Human stack first.
I also tried several other combinations, but nothing else has worked so far on both stacks. I'll try some more attempts if other spell strategies come to me.
Okay, your mileage may vary, but if you see these as options from the Ore Cart, then try them out as well as they may work for you.
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