You know, I will say this, though. It is true that there aren't really a huge variety of spider types in 5e. Giant, Phase and Giant Wolf, along with Swarm of Spiders.
BUT, that said, why not use ALL these types in the spider lair instead of 2 Ettercaps and 4 Phase and 1 mama plus some babies maybe?
So, instead of how it is now, why not start with two Swarms of spiders that attack almost as soon as you enter the Apprentice lair with her journals? Then, maybe 2 more as you round a bend. Thus, showing this lair is FULL of spiders. Then, while roaming, two Giant Wolf Spiders attack, dropping from unseen webs above. Then two more.
Suddenly, as you are nearing the mama lair, THAT'S when you encounter the Ettercaps. Then, finally, in the heart of her lair, you face Mama and 2 Phase Spiders with proper stats. However, Mama has twice Phase Spider stats and can cast some magic with spell slots, etc. Maybe she can Poison Spray you and such. Whatever. The point is, give us baby monsters to enjoy slaughtering that weaken the characters a little. Then hit the player with the boss fight. Don't make every fight so tough. I'd love that lair to be full of baby spiders and then Mama comes out to play.
