On one pass, without thinking about it, I wrote "They have jackets instead of hats." Is the definition of mantelo fine enough to exclude "jacket?"
Mantelo, by definition, is longer than one's waist. A jacket (jako), by definition, is down to one's waist. Elsewhere I've seen "mantelo" translated as cloak, or cape, so I guess that a "Manteleto" could be either a short cape or a jacket.
I don't expect the owl to know that, though.
I think mantelo is longer than a jacket <jaco>, although not necessarly heavier or thicker. It is not an overcoat.
"They have jackets AND hats" would be "ili ŝatas jakojn kaj ĉapelojn".
" kaj" means "and" not insteaf of.