It is probably best to use a non-toxic oil lubricant of some sort. Food-grade silicone is the lubricant used in most food processing plants. Mineral oil is suitable. REM oil and Ballistol are primarily mineral oil. I use Ultra-Lube which is a non-toxic vegetable based oil. I have not tried Frog Lube, but it should work as well.

Of course, the traditional oil for blades is Camellia oil.

Hoppes 9 would not be suitable as it contains solvents that are toxic, including kerosene and amyl acetate. It is a skin irritant, so it would be best to avoid it.