yes!

Pyracantha coccinea
Common Names: firethorn, scarlet firethorn
Family: Rosaceae (rose Family)
No not that I have seen.

Yes- but the thorns are going to make it VERY difficult to handle.

The poison in a Pyracantha is in such tiny amounts that being pricked by a thorn would not cause any problems.

The above may be true but I have found on several occasions when pruning our Pyracantha that the almost inevitable pricks by the amazingly sharp thorns will often leave me with a very sore and red finger or arm. This goes away after 2 or 3 days. This is possibly due to the minute amounts of cyanide in the plants.

It is believed to be so, yes, according to a commonly-held belief. However, more studies need to be done to confirm if pyracantha or Firethorn is indeed poisonous to livestock or if it's merely a myth that has been passed down through the ages.