Scenario is quite simple.
Whirler Rogue uses its thopters and targets itself. After it has resolves, opponent plays
Turn to Frog on the rogue. Can it be blocked?
Based of the wording of Whirler Rogue I would say that it is not granting the creature an ability. Thus it ought to change the rules of the game. I beleive this is quite similar to how
Shield of the Oversoul worked with indistructibility before that was changed.
I am not content with the rules references I have found though. Can you please confirm that the rogue still cannot be blocked after being turned into a frog?
Relevant rules text I have found:
109.3. An object’s characteristics are name, mana cost, color, color indicator, card type, subtype, supertype, rules text, abilities, power, toughness, loyalty, hand modifier, and life modifier. Objects can have some or all of these characteristics. Any other information about an object isn’t a characteristic. For example, characteristics don’t include whether a permanent is tapped, a spell’s target, an object’s owner or controller, what an Aura enchants, and so on.
611.2c If a continuous effect generated by the resolution of a spell or ability modifies the characteristics or changes the controller of any objects, the set of objects it affects is determined when that continuous effect begins. After that point, the set won’t change. (Note that this works differently than a continuous effect from a static ability.) A continuous effect generated by the resolution of
a spell or ability that doesn’t modify the characteristics or change the controller of any objects modifies the rules of the game, so it can affect objects that weren’t affected when that continuous effect began. If a single continuous effect has parts that modify the characteristics or changes the controller of any objects and other parts that don’t, the set of objects each part applies to is determined independently.
Example: An effect that reads “All white creatures get +1/+1 until end of turn” gives the bonus to all permanents that are white creatures when the spell or ability resolves—even if they change color later—and doesn’t affect those that enter the battlefield or turn white afterward.
Example: An effect that reads “Prevent all damage creatures would deal this turn” doesn’t modify any object’s characteristics, so it’s modifying the rules of the game. That means the effect will apply even to damage from creatures that weren’t on the battlefield when the continuous effect began. It also affects damage from permanents that become creatures later in the turn.