I agree with rodents of many kinds as being the culprit. I have been doing nuisance work for near 50 years now. Lots of problems with mice, rats, squirrels, porkies and groundhogs.
In the winter months I would have to go with mice, rats or squirrels. Never had a rabbit call. The damage may have been done prior to assuming the rabbit tracks are the problem.
Why don't you set cameras at two angles at near ground level to see if they are going under the vehicle and standing up to actually chew on your lines. They can't reach the lines without standing up. A cam will show this behavior.
The real question is where do you typically park your vehicle most of the time? Was the chewing done from the bottom of the brake line or the top. That is a critical piece of information for a diagnosis. Size of bite patterns tell the story in most cases.
Check under the hood of your problem vehicle. Most mice are living within the vehicle by this time of year.
See if you find any chewed insulation missing, look for nesting in your air cleaner housing container, and for any feces / droppings under the hood, on the battery or any flat surface area. The signs are there for the detailed pair of eyes and where to look.
Mice do lots of damage. I keep mouse traps set under the hood with hercules putty to hold them in position. This is done in all of our work and private vehicles year round.
We catch mice nearly every day in one of them. Snow cover slows their activity but it is open movement season when it melts and warms somewhat and snow melts.