kuseno

No suffix, and the false one looks official. The shape kus-en-o invites a decomposition, and the temptation is doubled because kuŝi (to lie down) is a real root that a pillow plainly has something to do with. Resist both. There is no -en- suffix in Esperanto - the official affix list has -ec-, -eg-, -ej-, -em-, -er-, -estr-, and stops. And kuŝ- is spelled with the hat: kuŝeno would be a different word entirely. Kusen- is one borrowed unit from French, and its resemblance to kuŝi is an accident of sound that happens to be semantically flattering.

Cushion and pillow are the same word. English splits them by where they live - a pillow is for a head in bed, a cushion for a backside on a sofa - and Esperanto does not. Kuseno covers both, and if you need the distinction you build it: kapkuseno for the head one, sidkuseno for the sitting one. This collapsing is very typical of the language, and the right instinct when you feel a missing distinction is to compound rather than to hunt for a second root.

Around the bed. Lito, dormi, litkovrilo for the bedspread, littuko for a sheet, and kuseningo for the pillowcase, using the -ing- of a holder. Mola is the adjective it wants; a hard one is malmola, and if it has gone properly stiff you want rigida, further down this same rank band.