That's what makes sense to me.
Bonus instances would allow you to, for example, to have two IATs out without them canceling each other. So yes, your example works.
As for ease of swapping, I'm just gonna have it be like shapeshifting for ease of existence.
Nice, that definitely works. Okay.
Oh, the first level of the Hugareida has to be a die bonus, right? That's what it sounds like, just want to confirm.
In that case, we need to assign the following Hugareida (my own suggestions in parentheses):
Forgefire: 2 Slots (+2 Dice when preparing to craft something, +2 Damage otherwise)
Emberwind: 1 Slot (+1 Damage)
Standstill: 2 Slots (+2 Instances)
Campfire: 1 Slot (+1 Dice)
Ignition: 3 Slots (+2 Dice, +1 Damage or, alternately, +3 Damage)
I'm actually sincerely unsure on Ignition, for this mission specifically. It's better assigned to dice if we're prizing endurance or fighting minions, it's better assigned to damage for single big targets. Personally, I think the +2 Dice (which gets us to +4 dice per usage), +1 Damage option is a better 'walking around' build, but I'm not sure whether longevity or raw power are better for this mission specifically.
If anyone's curious why +1 Dice, +2 Damage isn't being considered, it's because the first 'slot' spent on dice gives only +1 die, which is definitely worth giving up for +1 damage in isolation...the second slot giving +2 dice is much more arguable whether it's worth it.