Does Goomy's "Sticky Membrane" Ability increase the attack cost of attacks where the cost is ignored, such as when "Roto Motor" applies?
No, it does not.
Source: Forbidden Light FAQ (2018-04-20), TPCi Rules Team (2018-05-03)
Does Goomy's "Sticky Membrane" Ability increase the attack cost of no energy attacks like Alolan Marowak's "Limbo Limbo" attack?
Yes, it does.
Source: Forbidden Light FAQ (2018-04-20), TPCi Rules Team (2018-05-03)