jwl
For what it's worth, my book about Royal Enfields also shows the Indian motorcycles which were basically Royal Enfields with "Western style" handlebars and Indian paint jobs and logo's on the tank.
For 1955 and 1956 the book shows the "Fire Arrow" with a 250cc four cycle engine.
This was basically a RE "Clipper". It also had a Indian head ornament on the front fender.
In 1957, the Indian Lance was added to the motorcycles sold in the US.
The Lance was basically a 150cc two stroke based on the RE 150 Ensign II.
The other RE made Indians sold in 1956 was the Woodsman, a scrambler based on the Bullet 500, the Tomahawk, a 500cc twin and the Trailblazer, a 700cc twin.
The book makes no mention of a "Fire Fox" although one might have been sold in the US with that name.
If your motorcycle is a 2 stroke it is probably an early Lance.
If it is a 4 cycle it is probably a Fire Arrow.