This is a meaningless checklist; the only actual useful advice is to get the word out at meetups and such. The way you hire a data scientist is much the way you hire into any other team.

If you have a data scientist who is worth anything, he should be given responsibility for building the DS team. If you don't: you probably shouldn't hire one. If you must: hire one with experience, if necessary, as a consultant to build your DS team.

Putting physicists at the top rank is also a bad piece of advice; people with experience are at the top rank for DS. If it's pure fresh meat, you're better off with applied math people than physics people (and I am physics people).