Do any nonhuman species have effective ebola immunity?
While at least some other primates are suspectible to Ebola, pigs appear to be immune. From the WHO factsheet on Ebola (1):


  Although non-human primates have been a source of infection for
  humans, they are not thought to be the reservoir but rather an
  accidental host like human beings. Since 1994, Ebola outbreaks from
  the EBOV and TAFV species have been observed in chimpanzees and
  gorillas.
  
  RESTV has caused severe EVD outbreaks in macaque monkeys (Macaca
  fascicularis) farmed in Philippines and detected in monkeys imported
  into the USA in 1989, 1990 and 1996, and in monkeys imported to Italy
  from Philippines in 1992.
  
  Since 2008, RESTV viruses have been detected during several outbreaks
  of a deadly disease in pigs in People’s Republic of China and
  Philippines. Asymptomatic infection in pigs has been reported and
  experimental inoculations have shown that RESTV cannot cause disease
  in pigs.