Raw pork and raw chicken touching each other I bought a huge bag of pork bones, pork spare ribs and chicken bones.
To save time and space I combined them all and separated them into 4 bags and chucked them in the freezer. Now i'm not so sure about having the raw pork and raw chicken touching each other in the bags and when I defrost them in the fridge, they would be touching each other for another 10 hours in a less-than-freezing temperature. 

Is this safe?

(I am planning to use each bag at a time for making bone broth- boiled for up to 4 hours)
Yes, that's fine. You're going to cook everything to a much higher temp than the minimum safe temperature for the meat that requires the highest temperature. That's the key, and your plans are far beyond what is minimally required for safety.