You're extrapolating. Those aspects aren't part of the matter. There's nothing about these people that indicates they want to be alone. Making a tulpa literally depends on the person's desire for companionship, not their desire to be alone.
Schizoids are lonely and they choose (quite paradoxically) to be alone because of it. The internal fantasy of the schizoid exists solely to fill the hole left by their lack of emotionally intimate relationships.
That is, the steps of the schizoid personality is:
1. Loneliness
2. Escapism in the form of internal fantasy
3. Choosing to be alone, because the internal fantasy is judged to be enough
