You'll be just fine with that , Norcoredneck used a barrel that contained water-based machine lubricant in his tutorial which can be seen here.
http://www.bbq-brethren.com/forum/sh...ad.php?t=43943
Finding a food grade barrel only insures one thing , more work getting it cleaned out. As far as your kettle lid goes , they have a 22.5" grill at BigLots , that sells for $29 , you can use the lid and the grate out of it , not a bad deal really. Good luck.