Ahahahah. A bit of answers/thoughts:
1. HP: Initially I gave every melon to Urso to make him reach around 2k hp, then I used Emboldened Soul on Slagg phase 1. I then evolved Slagg two times to make them even bigger. After that, I gave almost every melon to Gora, at first, and then some to Mabek and Woad. I gave basically none to Gheist because he had to die, which sounds mean but he has fun doing it. Lol.
2. INT: I gave all the Int to Gora when I found it, I fused stuff into her with gave her much Int and used the mannequin training to raise Int and the event with the sage to raise their mana cost to raise their ints a few times. On the short run that option is not usually worth it, but on the long run it is!
3. TRIPLE CASTING: Too many Christmas presents ahahahah. I found lots of Circlet of Acuity and Harvesters, which for me, with the Prism, are the best Legendary Items.
4. SOMETHING'S STILL FISHY WITH THE STATS (MAYBE): There were a few times during the run in which I could swear there was still something weird with the stats. Like, sometimes I remembered one monster's stats being lower and I could not explain how they grew, but sometimes I was just paranoid, not calculating items and foods well enough, so I'm not sure if there is still something weird for real... I did not use many potions as the run before... Dunno, maybe there is something weird, maybe there isn't o.o''