What's best is to start one seed per pot...usually a smaller pot to start out so you can regulate the moisture on a smaller scale. To salvage what you have you can remove all of the seedlings except the stongest one from each pot. Do it soon before the roots get too intertwined. It may be best to just cut the unwanted seedlings just below the soil with a razor to avoid disturbing the chosen one.
So the one pot with 4 is easy... quarter the dirt and get em in separate pots, no need to play with the plants and the roots haven't gotten that far. These guys are insurance.
The other one... not so much. The ones that are a little bit by themselves will not be so bad at this stage, since the roots probably have not spread out so much as you have basically one good one going down. Heck even the paired ones if your careful you can dig out and remove from the dirt. Note that order though... You would want to remove plant(s) with dirt.. I would say 4" to 6" deep, and as far away from the plant as you can get, cutting evenly between the next group of plants. Lay them down on their sides on a flat surface. Being careful to see that most of the dirt spills rootward and not greenward. Let as much dirt fall away from the roots as possible before touching roots system. Separate, and place in new friendly home as quickly as possible. Transferring familliar soil is supposed to reduce shock.
The "Mongo" method (think the big guy from blazing saddles, helpful but brutal), and it could turn into a "Lenny" (Think the big guy from "Of Mice and Men", well intentioned... but a killer.) . Would be to turn the whole pot on it's side. Break a side off the pot. And carefully work your way to the bottom (other side).
I'd chose number one if I was gonna go all the way.
I use a dibble stick to separate my seedlings, rather than cutting down the middle. The dibbler sort of teases the roots apart, minimising damage to the roots. Cannabis is a hardy plant, and will tolerate transplanting quite well.
You may want to Google up "dibble sticks" to see what I mean. I have been growing and separating seedlings for decades using a dibble stick.
Recent update About 4 weeks. One of my plants survived through all the trial and error I went through on my first grow. It's still in my closet, Using 2 15 watt CFL white bar lights. Still at 18/6