All of them are considered headmates. I don't know anything about daemons, but I know a bit about tulpas and a lot about soulbonds. A tulpa is a being you create in your own mind, like planting a seed. You plant a seed and you take care of it and nurture it until it matures into a person. A soulbond is a fictional character that usually moves into your headspace from outside, like from another world or universe. I have nothing but soulbonds, 4 being my own original characters.
No because they were fan characters so they still came from outsourced worlds. A tulpa does not show up fully formed with their own personality and backstory, that develops over time as you nurture them into a person. All of my characters came to me from other worlds with personalities and backstories already intact.
A daemon, like Lorelay is in my case, are mental constructs. Basically it's a part of my consciousness I have given a voice to, the other side of my inner dialogue. They are inspired from daemons in Pullman's book, His dark material. Basically they are mental companions that represent you by their animal form. But Lorelay has his own personality, gender and tastes!
They're not imaginary friends because they're not imaginary, they're real people. I consider my headmates to be just as real as I am. They are all people in their own rights with their own thoughts and feelings separate from mine. They all had their own lives before coming to me, they have their own lives in the headspace. I did not make them up like you do an imaginary friend. They came to me from other universes.
If you're referring to tulpas, they are a lot like imaginary friends but you breathe life into them and they become their own individual people. The practice is not new and is actually a very old Tibetan practice.
It all works differently for different people. Members of a plural system could be splits from you, they could be spirits that moved into your headspace, they could be tulpas that you created and breathed life into, they could have just appeared in your mind without being splits or from other worlds. Its just different for everyone, but it all falls under plurality.
I believe my headmates are spirits that moved into my headspace. They all had lives in other worlds, then the majority of them died and ended up here. My headspace is like an afterlife for them. They are not disembodied souls cause they all have their own bodies. Not all of them are dead, but most are. The living ones are just ageless now. One of the living ones is still able to travel between here and her own world, or at least a part of her own world.
A person can have a combination of different types of headmates. They can have some splits, some soulbonds, and some tulpas. I only have soulbonds. Most are outsourced, a few are insourced. But the insourced ones still came from other worlds, so they're partially outsourced.