This is something I've always wondered about, so here it goes:

 

Does your Beastiary fill up quicker if the character making kills has a high(er) Lore skill? As in, if e.g. a Lore 5 guy kills all your Black Oozes or whatever, will you need fewer kills to get all the stats, HP and abilities and such for them, compared with a Lore 0 guy making the kills?

 

In my mind this would be logical, but has the game implemented it like this?

No, it's purely based on how many of a given creature you've killed. That's a pretty good idea though, perhaps something to be implemented in the sequel in Obsidian are reading this.