"Abaca fiber is not snow white to begin with.  It's a yellowish off-white so bleaching is unlikely to help.  There may be a dye that will work.  Jacquard fabric paint will work for sure."

"Have you tried drying it with a hair dryer instead of steamer?"

"There is a method of making hat blocks out of expanding spray foam.  The stuff used for sealing cracks and around windows.  It's vailable at the local hardware store.  It's decribed on youtube. Once you have the big chunk of…"

"I grow fancy chickens for their feathers.  I do not use  large plumes but sew small individual feathers onto a backing to make hat bands, headbands, feathered lei, etc..  See above for washing and killing mites.  You can also use…"

"It may be because that is the way they were originally shaped.  I would try steam ironiing the brim,  The heat and steam might make the felt hairs reorient themselves enough to stay flat.  The steam may reactivate a water-based…"