Back to the original q. Not only can you have fish and meet i the grill you can even do it ben Yomo! As long as you let the grates get burned out, it should really be until they become white (ליבון גמור) but if you want do ליבון קל and just make sure they so hot that if u out a tissue the tissue might catch on fire or shrivel up.
And as far as CV being allowed to cook for us, if i ain't mistaken theres possibility to marrying his kids...(ע׳ שו״ע לגבי פס עכום) but if CV called us over for some French fries itll be ok (if i may recall) bec its not עולה שולחן למלאכים.