Shouldn't put buttons on them (choking hazard) but these would be easy to do from felt or blanket material. Like the jingle bell inside. cute little baby rattle. free pattern and you use jingle bells for the rattle part.
DIY Tree Branch Seahorse **Mi(my) WAY: combine with the idea of the lit wood Christmas tree on the canvas, do any shape on the canvas then add lighting. Or weave lighting through out or around the seahorse or whatever u design.