Renewables can absolutely provide and consume reactive power through the use of power electronics equipment incorporated into the inverters. All modern utility-scale wind and solar power plants use this type of equipment, and most interconnection requirements in the US require significant reactive power capability as part of the interconnection process. This may require additional reactive power capabilities such as capacitor banks, DVAR units, or reactors at the project substation.

This means if grid voltage drops they will provide VARs to increase voltage, and vice versa. They can similarly react to shifts in grid frequency. Only after they reach certain power factor, voltage, or frequency limits will they disconnect from the grid, similar to other generators.

If in spain renewable energy projects were somehow exempted from needing to provide a wide range of power factor capability then yes this would be a rules problem.

They charge more for inductive loads because of low power factors and significant VAR consumption yes, though you can also do power factor correction on induction motors. And though most wind turbines use induction generators, they are designed to be able to supply power at unity power factor and through a large power factor range.

Also, islanding means operating as a standalone grid, which does not happen when the generators shut down, and systems are designed to shut down after a certain number of cycles without grid. This does not sound like islanding at all.