@Degernase
I think those are some pretty fair assumptions to make. The only thing I would contest is the types of spirits that tend to exist. There are a few more types. There are spirits that get attached to people and follow them around, or are attached to a specific location and just stay there. We've seen that. There are spirits that seem to survive entirely by possessing the living and influencing their behaviors. We've seen that. There are what I'm going to call "weirdos," which are just strange spirits that hang around and don't really seem to have any attachments, like the vending machine squid man and a few others we've noted in the background. And then there are the spirits that do seem to have some purpose or design they are pursuing, something that motivates them, like the axe guy, who seems to spend all his time hanging out on buses and trains and fishing possessor spirits out of people so he can stuff them in a sack and do... something, with them.
There are also literally just straight up ghosts, which I think deserve a typing of their own. Just the souls of dead people, who aren't mutated or distorted in any manner. You can even talk to them, if Granny doing so to the dead husband of her friend is any indication. Dead humans seem to be completely safe, though we may see that tested in the near future, if any of the victims of vigilante teacher come back. If it weren't for that freakish thing that ALSO seems to live in her house, we don't have any reason to suppose she couldn't talk to her father and let him know she can see him. The only reason would be that informing him would also constitute making it aware that it can be seen, which would, of course, not be a good idea.
We do still have a few very important questions that don't have answers. One of which is, can she even BE hurt by these spirits? I'm not saying they pose no threat at all, obviously they do. But so far, we have yet to see any of these spirits actually injure anyone. She ASSUMED axe man's axe would cut her, but would it really have? We still aren't entirely clear on precisely how dangerous ANY of these things actually are. They pose some amount of threat, between the amounts of almost nothing to horrific. It's somewhere between those extremes. We don't know where.
We actually have a good grasp of their power levels, though, because the attendants have shown us that. The mutated hag is the most dangerous thing we've ever seen. It killed both attendants and required the Inari/Kyuubi/Fox God to intervene directly. The trashcan spider was extremely dangerous and absolutely outmatched the kids and all the other ghosts present, but wasn't strong enough to kill even one of the attendants. The ambush kid was stronger than the trashcan spider: unlike it, the kid was able to kill one of the attendants, which means that the kid is actually VERY strong. That was a completely unfair and one-sided encounter for any spirit medium. It's basically the supernatural equivalent of a trapdoor spider or anglerfish. And finally, the mother was stronger than the trashcan spider, but not as strong as the hag. Like the ambush kid, she also killed one of the attendants before being put down.
One of the things I really enjoy about this series is the air of mystery and danger. There are a bunch of very basic questions that we still don't have answers to, and absolutely nothing is made clear. Even the authorities on the spirit world, like Granny, are very obviously shown to have limited knowledge. Granny can't see the reapers, and doesn't know anything about them. Hopefully, we DON'T get clear answers to any of these questions soon. We will probably find out more about the attendants and the Fox God, because they seem to be making themselves part of the plot now that they've intervened the promised three times, but I hope that a lot of the basic questions about the setting continue to remain unanswered, at least for a little while.
We will probably get some answers, though, because obviously the Goth Urahara magician is being set up to provide some exposition. He's the only other person that could see the Fox God. But hopefully he keeps his explanations to a minimum, because it's the mystery of all of this that makes it so good. This story is much more frightening precisely BECAUSE of the fear of the unknown. Once we know things, it becomes substantially less scary.