There's a good core of an idea here. Getting a special item in a box that provides a certain benefit would be nice and fun as well, if it was random.
Maybe after nodes 6, 9 & 11. Most of your items seem good, but I'd want the item to be usable between GW battles, not during them. 100% TM allows you to see the TM status of each toon in your inventory & grant 100% to the one you want. That toon starts out the next battle going instantaneously. Regenerate protection does not add +100% protection, it returns your protection to 100% so if you still had some left, you wouldn't get more than 100%. Regenerate Health would return a single toon to 100% health.
Taunt would be interesting - you could give taunt to any single toon before a battle started, even if that toon is not normally capable of taunt (Dooku, anyone? Maybe 5s?). There could even be different versions that give taunt for a different number of turns. Imagine giving your toon a Taunt 5? You KNOW that toon is guaranteed to die, not like a Taunt 2 where it can soak up some damage, get healed, and continue fighting. On the other hand, you can give it to a worthless toon like Nightsister Initiate who has a lot of health but doesn't do anything good for your squad. By making sure your damage dealer survives a couple rounds, you can use a Taunt5 + a suicide squad to actually take out the enemy lead on those horrible zeta-lead teams.
The real question would be whether or not these special items disappear when you reset GW or if you could save them up on days when GW is easier for you and spend more than one at a time when facing a super-hard node. You shouldn't have to use them on the node that you get them, but being able to save them up for multiple days might be OP.