I'm not particularly familiar with the hazards of mouse/squirrel chewed wiring, so my comments are general.
For the hazard of shock, new wiring is useful because it ensures an intact EGC (ground). GFCI is useful because if you are getting shocked hot to ground (rather than neutral), it will detect that and interrupt the circuit. AFCI is not particularly useful, other than to the extent it incorporates GFCI-type technology.
For the hazard of fire, the concern is heating due to a poor connection with a high resistance. New wiring is useful because it will eliminate the damaged sections that may have high resistance or faults. GFCI is maybe useful, as it would detect any hot-ground faults that could cause current flow and heating, but not hot-neutral faults. AFCI is maybe useful--it claims to detect certain types of arcing faults, but I'm not aware of anyone having gathered real world data to show a reduction in fires. And manufacturers grossly exaggerated AFCI's capabilities when they were first required by the NEC, so I am rather skeptical of anything they have to say on the topic.
So I see new wiring as the best/most important mitigation method. GFCI is a simple proven technology that is partially helpful. AFCI is a complex, as yet unproven technology that may be helpful.
Cheers, Wayne
P.S. It is possible my information is out of date, perhaps data has come out in the last 5 or 10 years showing that deployment of AFCIs has in fact led to a reduction in fires. Even if that is the case (I would be interested in a reference), it is at best a second line of defense, the first line being properly installed, undamaged wiring.