Particles and sound are a great way to differentiate spiders but it would be cool if they come in different sizes too, being Mother Spider bigger sized and their childs smaller sized than the rest of spiders.

Idea: Spiders attack silverfish because, well.. Spiders eat insects and you can right click to grab a silverfish and feed it to a spider and tame it

I like how you took one more step & added new spiders instead of only making the normal spider the only spider capable of throwing webs!

Interesting. I have some suggestions:
1-Change the from "Better Insects" to "Better Arthropods": Sspiders aren't insects.
2-Cave spider should not shoot webs: Balance & parity with MC Dungeons.
3-Less destructive silverfish: Maybe make them turn invisible & still to "hide" when on stone or any of its variants except ores, Nether & End stones & then make them visible & mobile again when a player comes close.
4-Endermite changes: Make endermite spawn naturally in the End. Endermites could have the same "hide" ability that silverfish have but in endstone instead of stone. They could also drop 1-2 endstone.

Thanks!