At chemical forums we do not provide advice about how to make medications, drugs, cosmetics or edible products. Therefore this response is addressing the digestibility aspect of the question, not the edibility aspect of it.
Although hair is basically protein, the keratin component of hair is tough and resists digestion even in harsh conditions because of the numerous dissulfide bonds that hold peptide strands together. The best way to digest hair is to first use a process that can hydrolyze these bonds, rendering the proteins easily digested by normal peptide digestion methods. You can buy keratinase at many chemical manufactures that should be able to do this under reasonably mild conditions - although these can be expensive depending on how much hair you are trying to digest.https://www.sigmaaldrich.com/catalog/product/sigma/k4519?lang=en®ion=US
Treatment with reductants like beta mercaptoethanol (or TCEP) may provide an alternative chemical means of loosening the dissulfide structure, rendering hair digestible.
If all else fails, high temperature acid or alkaline digestion will also probably work, but a properly equipped chemistry lab and technical knowledge will be required to do this safely and effectively.
To restate: just because a protein is rendered digestible does not mean it's edible
. Any chemical treatment can introduce unsafe chemical residues that would need to be effectively removed before you could actually ingest anything you make or transform in the lab. This process would probability be more difficult than the problem of making keratin able to be digested in the first place.