Maxxed, unemblemed Buddy - Buddy’s Special creates minions with 132 HP for himself and nearby allies.
Maxxed, unemblemed Buddy and maxxed, unemblemed Santa - Buddy’s Special creates Minions with 198 HP for Buddy’s Minion but only 132 HP for the nearby allies - expected behavior since Buddy gets the family buff and the nearby heroes not being Winter Family members do not. Buddy’s base minion with Santa on the team is way off though. He’s getting a +50% boost, not a +05% boost.
Testing further, with Santa/Buddy/MN on the team, I should get a +10% boost, so Buddy’s Minions should yield 145 HP. Instead, I’m seeing 264 HP. Enjoying the +100%, but it’s too much.
I didn’t run full testing with all the Winter Heroes, but it appears to be across the entire Family. MN firing in the Santa/Buddy/MN scenario, and then Frosth on top produces a Minion with 487 HP! Also not sure if any other Families are affected, but testing their multi-family buffs are a little harder to calculate/validate.
Wish this was tied to something external so I could grab a bug bounty.