Please help ID 4 different tenants living on my frogspawn

[rvamarcel]

I have a spiny jewel box about the size of a dime.

How can I tell if it is alive?

 

[stevo01]

How can I tell if it is alive?

Tap the shell. If it shuts tight its alive.

 

[stevo01]

Otherwise its a cool ornament hahaha. Looks like it has some corraline algae growing on it.

 

[MicroPico]

For the ruffly guy, I was thinking scrolling coralline algae. I truly cannot tell if the duster is in fact a duster. The other two seem like tube worms of a sort or vermetid snail if it has webbing coming out & around the end of its tube. I would keep watching them to see how they function before I glue them. Maybe a clearer closer pic if you can. I know its hard to do.