Oh, heartbreaking for poor Biscoff and for you
What was he there for in the first place? Is his original problem OK?
One thing I do remember from previous threads is that the loss of a hind leg seems to be easier for them to manage than the loss of a front one as the front legs bear a lot of weight - those big heads are heavy! But with a hind leg if they get tired they can just sit down a minute. I hope they have given you plenty of painkiller for his recovery journey.
As far as his front teeth are concerned as long as the break was clean they should be able to grow back and level up against the bottom incisors but keep an eye on them... if they start to look like the edges are slanting instead of straight it can indicate chewing to one side so you might have to go back to a vet to have his mouth checked over again. He will be tender for a while and might be unable to bite at things but by cutting his veggies into thin strips or little chunks, and by helping him get them into his mouth, it should show him that he can still manage. There have been piggies on the forum who are completely missing a pair of incisors and they had to relearn how to eat but they adapted well.
We'll be thinking about you all. Biscoff, you're a very brave boy x