Apart form the glue issue what one treats a chopping board will make or break the project. If you are doing these for yourself, that is one thing but for friends or paying customers one would need to be extra careful. If at all possible use a certified food safe product then you can be assured there are no health aspects.
Many non hardening oils are OK but being non hardening, they wear and wash off too easily. Yes, saturation is necessary but no build up should occur as that will hinder any touch ups later on.
The Livos Lady