Now that the ash is in Barbados and St. Lucia will it also impact other islands?

Yes. Wind will carry ash further away from the volcano with time. Surface or sea level winds will carry ash west and south to the Grenadines and Grenada. In the upper atmosphere winds will take ash north and east. Islands like Martinique and Dominica may receive some ash, but the majority will go out into the Atlantic Ocean or the Caribbean Sea.