I sometimes feed Coco pork ribs with no problem - I don't think the bones are any more likely to splinter - as far as I know it is only cooked bones that splinter not raw ones. Some people don't feed beef bones though as they are harder and can wear the teeth down more.
You need to be sure that he is crunching up bones properly though whatever sort they are. I know some people don't like to feed pork though I never know why - have you noticed that none of the ready made pet foods are pork based?
I do freeze the ribs for a bit first as I understand it kills off the harmful bacteria in pork. Don't expect the vet to approve of BARF feeding - not many seem to be in favour of it. My vet said "It's better to feed a ready made complete food" Seems to me that is like saying it is better for us to live on pre-prepared food rather than a fresh, balanced diet.
Re switching - I did it gradually because I had a load of Naturediet to use up but I know a lot of people recommend doing it in one go. I don't think it matters - some say it is just important not to feed processed and raw food together so Coco had Naturediet in the evening and BARF for breakfast to start with. That way she had a good 12-14 hours in between