I can't see that Integrity vote going as planned. Utau might let us borrow Eru maybe once, max, before she realizes what's up. Eru is going to stop cooperating too. I'm less confident about how Ran and Su will react - with their closer tie to Amu's mental state, they might be feeling a lot of what Amu is feeling.
There's a reason I wrote that Integrity stunt with the wording: "as much as you can manage each day". It's not actually meant to assume very much.
The only thing we know is that Amu cannot handle more than 2 hours Integrity training per day, we don't know how much she actually can. Could be 10 minutes, if at that. There's no real way to find out without trying, but it also wouldn't be very effective training if she wasn't pushing her limits.
....I'd also like to point out that nobody else apart from me came out with any suggestions on how to train Integrity. And I can tell you, every other method I can think of for training it is worse and less low-key than asking to borrow someone's Chara or seeing how long she can keep Ran and Su out.
The least problematic of the alternatives I can think of is trying to keep her Charas loaded/herself Chara-transformed as long as she can, which requires absorbing Miki for extended periods of time. The other methods involve asking either trying to nudge Dia awake, getting other people to try and force their mind onto hers (most likely morally-grey people from JP's or the Scavengers, as her friends would almost certainly refuse) or attempting to replicate the possessive demon/persona summoning that she did when healing Saaya and purposely losing herself in the Sea of Souls/Road of Stars.
Huh. Those are some weird rolls. One trait vs. another? It's not "one die per trait, higher roll wins" - that wouldn't make sense for the 3-die rolls. Somehow we're rolling Integrity vs. itself, too.
It's not just "one trait". The first 3 rolls all involved Integrity.
My guess is, that single stat is the sole reason we need dice rolls at all (taking into account QM's mention of Amu needing to pay special attention to training Integrity) and those rolls were for the overlap stunts involving Integrity to see whether Amu's attempt to train it at the same time as Dreamwalking (using Eru at the same time as linking with Ami), Lore (studying while Ran and Su are externalized) and double up on itself (borrowing Eru while Ran and Su are outside) succeed or ends up with her too exhausted to actually pull it off.
We got successes on all 3, but we don't know how many we actually need to "fully" succeed. We got 2 on the Lore roll, probably means it fully works and she studies just fine with Ran and Su. We got 1 on Dreamwalking + Integrity, that probably means we got some overlap with Dreamwalking and it goes mostly fine, no guarantees on the quality of her actual sleep. The Integrity + Integrity one only got 1 success for 3 dice. If it needed 2 to fully succeed, my guess is that's it's either going to leave her exhausted but not enough to completely crater the training attempt, just not enough to get the full 2 hours for it. Maybe an hour or half an hour. In the worse case, that roll might have been for how much of a penalty to apply to Amu and she avoided getting carted her to hospital, but lost a few hours on training time due to people noticing her nearly fainting from the attempt.
But as you said though, "Overgrowth" sounds like a bonus rather than a penalty, so likely we only need 1 success to pass all 3 and then got a chance at extra because of it. And then got a critical success on it, meaning either more overlap percentage than normal, or she comes out of the attempt having "opened up" more hours in a day to do it (i.e. than if her friends/family got worried about her and tried to force her to stop).
Considering Int came up in those rolls, it's possible Int has some influence on how well trying certain things go as well. Which narratively could make sense as well...
That was my first guess and that 2 of those dice came from having 2 levels of Int.
My second guess was, the mention of Intelligence might indicate how this gets implemented from a narrative perspective - either whether people notice that her cramming and newfound knowledge (possibly including her sudden prowess at Dreamwalking and Illusion) is unnatural, or just get convinced that Amu is simply naturally that smart and talented (2 dots in Int is not really dumb and, given the right circumstances, could probably get mistaken for 3 dots in Int or higher).
.....This list of people might actually include Amu herself.
There are definitely healthier ways to narratively flavor the training. Further story events, and differently worded training votes, should hopefully change the narrative flavor.
Oh come on guys, I came up with like 3 drafts of this stunt and I don't remember anybody (apart from maybe the QM making some shifty comments) seriously bringing up healthiness as an issue when I mentioned how masochistic the idea of training Integrity was. I thought everyone was fine with it.
If you guys can think of a better method that both grabs as much extra hours in day as possible for training 4 different stats at once - including Integrity, of all things - while overlapping them in a way that keeps Amu fit and healthy mentally and physically, please do.
'Cause that was the healthiest way I could come up with.