Feather dusters require little or no intervention on your part as far as foods are concerned. They are considered fine filter feeders and the foods you mention are far to large for these food types to benefit the dusters. They will however feed off the DOC
in the water quite well. If the tank is still fairly young (<6 month) you could suppliment with some Micro-vert and/or live phytoplankton sparingly about 2-3 times a month.
The mushrooms will on the otherhand benefit somewhat from the addition of very fine meatier foods but will be almost as independant with the correct lighting.