Well, first, I did not ask you what YOU thought about DID and tulpas but WHERE you heard someone suggest the link.
Secondly, you are very wrong about alters. As I said, I have a dissociative disorder and, not only am I
an alter, but I know my fellow alters well enough to know that we are people, not emotional states. What you are talking about sounds closer to someone who is a "median". Those people attribute separate emotions to other versions
of themselves, which may not be considered alters at all. Each alter, in my case, is different. Some are more angry or happy than others, but I would never say that So-and-so is my anger and Such-and-such is my happiness. If an alter is angry all the time, it is because he has some very traumatic memories from some point in our lifetime and he has trouble coping with those memories.
Third, I don't think using a self-help diagnostic scale for DID is best because DID is one of the most severe dissociative disorders. People with DID have the most problems with amnesia due to a lack of communication between alters but amnesia itself is not a qualifier for a dissociative disorder. Since I do not have trouble with amnesia, I only got a 17. DID, of course, is the most famous dissociative disorder because it is catchy with the media, so I don't blame you for using DID. Still, Otherwise Specified Dissociative Disorder would be the best condition to explore when it comes to ease of tulpa creation.
Back to tulpas, I think my brain's tendency to dissociate and create new entities is what makes it so easy for my fictional characters to "come to life". This is something I have already thought about and I am glad to see that I am not the only person who believes there could be a link between the two.
PS: One of our goals in life is to bridge the tulpa and dissociative disorder communities.