Welcome to the mudcat forum. I was wondering, how old is your son? That might affect the size of the instrument that he's going to start out with. Violins/Fiddles come in 1/4 1/2 3/4 and full size. Getting the right size is really important.
Does your son read music? If he does, Carol Ann Wheeler has published a book, "Children's Fiddling method," which she published to suppliment the Suzuki method after about the first year.
It might be helpful to have a teacher at least show your son how to hold his instrument, how to hold the bow, the correct tension on the bow, how to rosin the bow, and the correct set up for his shoulder rest and chin rest. You can learn these things by looking at pictures from a book, but believe me, a little help goes a long way. There is a Mel Bay publication, I think it is called "fun with the fiddle" that covers many of these issues.
Finally I would suggest that you and your son might interview the teachers to find one whose style he enjoys. Go and ask the teacher to play a few fiddle tunes for you and see if you like the style. See if your son hits it off with the teacher---and if the teacher hits it off with your son. Otherwise, your son will wind up really frustrated.
One final note in the difference between fiddle style and violin style is that a lot of energy is spent in the classical style learning vibrato, which tends not to be used so much in "classical" fiddle style.
Finally, it is possible to teach yourself how to fiddle without the benefit of lessons and without the benefit of classical violin training in your background. I did.
Tell your son from me "Happy fiddling."