When a creature becomes warded, place a ward status counter on it. If a creature with a ward counter on it would be damaged, destroyed, or leave play, instead discard each ward counter on it. (Note: This prevents the creature from being tagged for destruction.)
While a creature has a ward counter on it, it cannot be warded again.
If a ward counter is placed on a creature after it has already been tagged for destruction, the ward counter will not prevent the creature from leaving play. However, it will prevent the creature from leaving play in other ways, such as being returned to hand.
Once a creature has been tagged for destruction, it's too late for the creature to be saved by a Ward. While a Ward can prevent a creature from being tagged for destruction, it will not prevent an already-tagged creature from leaving play.Source: Crucible Cast 17
Arcana Advises: Yes in both cases. Explo-Rover's ability acts as a replacement effect for how the card can be played. During a turn where Star Alliance is the active house, Explo-Rover can be played as an upgrade to get around play restrictions such as Lifeward. Explo-Rover's ability can also resolve for the purpose of resolving Matter Maker's ability, allowing it to be played as an upgrade as if it belonged to the active house.For more information about Arcana Advises and Outstanding Issues, click here.