*"How did the guy from That 70's Show know that one plant was poisonous?"-He explains at one point or another that he studied poisons and toxins. Yes, I remember that part, but how is an expert on poisons and toxins from earth going to be on an alien planet and know a dangerous alien plant from a non dangerous alien plant??
*"and what happened to all the alien dogs?"-I sort of remember them being killed at some point but I may be mistaken some were killed except for like 1 or 2. they were later seen again when the humans found the predator camp site. but then that was the dogs' last time being seen again in the movie