Okay, I finally bit the bullet and started trying out some companion mods. CM Partners has some nice features but it's full of bugs and is really hard on my framerate. Companion share and recruit is also pretty good but I don't really care for recruiting vanilla NPCs and most of the extra companions I've found for it require other mods that I don't want to install.

Really I'm just looking for maybe a small pack of companions that I can choose from that aren't too heavily scripted, don't have custom voices and don't require any fancy content mods like hair and eye packs. Preferably companions that aren't overpowered or over-equipped. I do have Vilja. She has a custom voice but I'm willing to make an exception for her. So that's one but I want a few more.

Companion Fergus is a recent one, although fully voiced and is not what you are looking for in variety (Cant link it falls under advlt content, though not sure why) - I mention it because if you have Vilja Installed Emma and CDCooley have been supporting the author, I think there is going to be a bit of interaction between Vilja and Fergus in the dialogue in future. Still early days in development but maybe one to watch.

Edit: A bit more helpful, its on TESNexus. Also have a look for Stoker Wolff, Mondstein, Neeshka, Sonia II, Ruined Tails ... Hmm, cant think of any packs.

I'd recommend you have a look at Valeria and Vicente as you can actually tailor them ingame to be the classes you prefere. Neeshka, Sonia and Rhianna are also matching the purpose you mention. All of these companions have unique interaction with Vilja (or rather, Vilja has unique interaction with them) and are no heavy downloads as they use the game original voices.

Oh, and there will be interaction between Vilja and Fergus (he and Neeshka are the two companions that I generally have in my game, alsongside with Vilja of course). Although this interaction with Fergus is not yet available, as he is still so new and Marek and I will look over it together.