Four quick yes or no questions that I think would clear up everything we know about this ability.
Does Ring of Magnetism affect all actions and abilities so long as they are ABLE to target characters? (Powerbolt)
Even if the character it's attached to is not a valid target for that ability? (Thrown Car, Magneto)
If the character is not a valid target for that ability, can that ability be used at all? (Steals it or Fizzles?)
If the ability has both a targeting and non-Targeting component, can it still be used? (Blessing's Burst Side)