How does this piece of Vasitha's yoga fit with Buddhist thought? One of my favorite lines from Vasitha's yoga
"I am not,  nor is there other,  nor is there nonexistence."

In what ways does this parallel with Buddhist thought? 

In what ways does it differ?
Yes, in regard of Upasaka Thiago Silva answer. 

Seems like the approach of what the Buddha called "the Uposatha of the Niganthas (Jains)"

See: Muluposatha Sutta: The Roots of the Uposatha