There are usually plenty of coils cheap on fleaBay; they don't go bad very often.
They are made in one piece, and obviously the spark plug boot is a very specific shape with a seal, so replacing the whole thing is about the only option.
That said, on some vintage bikes we've found that the wire can often be unscrewed from the coil if you can get through the sealer or glue they use and get it to move. Inside the coil you'll often find there's a pointy little threaded bit, just like the end of a wood screw, that's meant to sort of thread into and bit into the core of the wire.
Whether Vee coils are made like this, I have no idea.
Also,FWIW, folks on vintage forums have had very mixed luck (usually poor) with salvaging damaged spark plug wires using coverings, silicone, etc. Worth a shot for a few days, I suppose, if it's your only vehicle.
As far as how the damage happened, I'm not 100% certain it was critters. Usually the tooth marks are more apparent? But maybe not. Really hard to say from one photo, but definitely check the surrounding parts and make sure the tank mounts, etc. are in the correct positions to make 1,000% sure nothing was rubbing and the tank is held up in the correct position. Those damn stupid rubber blocks on the sides, for example, just love to disappear; mine are duct-taped to the frame.
2002 Suzuki DL1000 V-Strom, Dark Metallic Space Blue
1983 Suzuki GS850G, Cosmic Blue
2005 KLR685, Aztec Red - Turd II.2, the ReReTurdening