it was a just in case situation as you are putting what it looks all the main mods, why not some others that while bad are well known.
The bosses are a different thing, apart from what you have put in already i think they are some of the best bosses i have seen till now in Quake and we need more bosses: while the anaconda has the issue of half its model can't be hit it is an awesome looking one and good to fight against and some mappers will find the way to overcome its downsides, and the lava worm is an actually good and well done boss and could do wonders with the lavamen from DoE acting as its minions. If you want to try it, it is in the last level of the Virtus episode (get some ammo, noclip to it and enjoy).
Willy the spider is a normal looking spider, with the width and length of an ogre, a good model, it uses the sound from the shalraths and a single hell_knight's projectile. A bit nonthreatening but it is common for maps in 1997 and 1998, some people maybe will use it for laughs and it won't harm the pack being there. You can see it here, for example
https://www.quaddicted.com/reviews/housp.html
The snakemen is used well here, for example, if you are curious
https://www.quaddicted.com/reviews/alk05.html
Never knew about that pack, i know about those two enemies from the many maps they are in, but it is something to take into account for mapping.