I would not have all the Hot and Cold Things chosen on the same table. I would have them on two different Tables. This way if a future thing needs to give a bonus Hot you can just increase the count for that table.
You already have abCategory.? tags to use to easily separate out the Things on to Primary and Secondary tables.
In regards to your question abCategory.? tags are pushed directly to the Hero. This means your transition is simply the hero itself.
Code:
hero.tagcount[abCategory.Cold_tech]