Just a funny thought.
Could you use
Merry, Swordthain to play x2
Horse of Rohan on minions like
Easterling Host or
Saruman, Agent of the Dark Lord to make them exert at the start of each of their skirmishes? That could be fun.
EDIT:
The only thing I found in the comprehensive rule book on this was
"Playing possessions
Play Free Peoples possessions under a character,
with the left edge of the card visible for its card
title and attribute bonuses (positive modifiers
for the character's strength, vitality, and/or
resistance, written with a plus sign like "+2").
Some possessions play to your support area."