[Crex]

1 - looks like tip of water buffalo horn and section of stag
2 - Tauga nuts....vegetable "ivory" often used in netsuke carvings very hard, small hollow in center. Often used as an ivory substitute by scrimmers and carvers. Makes nice spacer material if handled right.
3 - more likely copal than plastic. copal is a pre-fossilized stage of amber. try a heated paper clip - touch to material the smell will tell if copal or plastic. Plastic will smell like plastic and copal will smell like pine pitch.
4 - jigged WB horn
5 - Top two long pieces are bone - dyed and undyed - can't tell you what kind.
The bottom small pieces look like ivory cuts, sand to very fine on ends and look for patterns will look a lot like heliographs than wood grain and not porus.