power and cast speed should be theurs primary concern. you must spam a lot of pets and do it fast as you can. pets have percentage cost so bigger power pool doesn't help you very much. imho theurs successes in fg is measured by how long you survive and how long it takes you to fill battle field with your pets. so i would ignore damage,crit, int ras.
i would consider raging power. cast speed also important so mastery of art and aug dex is two viable option. rest is really optional. i would go more survival line such as toughness, aug con, psychical defense,
note: i would also test mastery of focus if it effects pet level
probably not but if it does, pick it asap.