Soul....

1. an entity without material reality,
....regarded as the spiritual part of a person.

2. the moral or emotional nature of a person.

3. spiritual or emotional warmth, force, etc.

4. vital or essential part, quality, etc.

5. a person.

Soulful....

1.full of deep feelings.

Spirit....

1. same as soul.

2. life, will, thought, etc.
....regarded as separate from matter.

3. a supernatural being, as ghost, angel, etc.

4. an individual.

5. disposition, mood.

I tried searching for "Old Souls" in the search engines. I got side tracked by Mandalas. I spent years (ago) coloring Mandalas. In fact they were an important part of my study into color and the simplist shapes.

I did find some interesting articles about Spiritual Astrology. They're by Jeri Noble at http://circlesoflight.com/articles.html#astrology

As Plutonian that I am,.... I will be adding to this section. Each to their own.... If it works for you that's what counts. If it doesn't.....Then keep searching until you find what works for you.