and that combination is correct! Moebelle got one originally (babirusa) but robmv got everything else and guessed the theme, so he is the Grand Winner of this round. I'll link to the original photos in a minute.That riddle is more confusing than the photos! The only combination I can come up with is:
1) Babirusa
2) Warthog (which would surprise me)
3) Pygmy Hog
4) Bearded Pig