Is it possible to change the source MAC of all the outgoing ARP requests to a specific MAC instead of using the interface MAC in linux?
Is there a way to do this from the ARP tables?
Yes, this can be achieved by adding rules by arptables.
Use this rule:
arptables -A OUT --source-hw xx:xx:xx:xx:xx:xx -j mangle --mangle-hw-s yy:yy:yy:yy:yy:yy
You may also add more filtering options if you need example interface, subnet etc.
For more information, refer to the man page.