I really like the "lost stuffed animals" idea for these two, but on closer inspection, it seems very unlikely. The main reason is that the tall one has a bone sticking out of his sleeve; no matter how "rough-loved," stuffed animals do not have bones. However, he definitely has a circle of stitches around his head. Lobotomy? A very strange, lopsided lobotomy??
The wheelchaired one also has lost both of his legs, but the remaining appendages are the same length. This suggests a train or car crash rather than leprosy. Then again, the bone-showing of the the tall one suggests leprosy. OR, that he knawed himself out of a trap?
Also, does the wheelchair guy have a right paw? It's never shown; it could be the hand which is moving the wheelchair though.
Not sure I want to know, but what is the tall one's huge collar/scarf covering up? The high placement of his ears suggests that he is a dog or cat who has lost his ears. His mouth also looks dog-like, but the lack of tail makes one wonder.
Also, look at the tunnel. Are those wheelchair tracks coming out? Possibly these two live together in the abandoned tunnel and wheel/walk out every night. Also, note the wheelchair tracks in the final panel; the guy has turned all the way around in place and headed back. Not sure if that means they're going to the tunnel again or not, but it's cool-looking.
(I've looked at the pair for so long now that I'm not sure they'e still scary. Hooray.)