I would never let my snakes around my 4 ferrets. Ferrets are crazy and could kill them, and snakes could defense strike, and yeah, no.
My dog can be in the same room when I'm holding the snakes or my Bearded Dragon because she is very well behaved and has grown up with reptiles and..everything haha.
Ferrets are just...ferrets haha You should get two ferrets, never really just one. Ferrets are extremely social and really need another ferret.