Does the NHL or any other league provide guidelines for use by league statisticians? E.g. for giveaways, takeaways, checks, possession, etc.
No, there is no official manual for statisticians from NHL on the web. There are only some articles explaining some advanced stats like Corsi, Fenwick, PDO... (https://www.nhl.com/lightning/news/hockey-analytics-101-understanding-advanced-stats-and-how-theyre-measured/c-735819).
However there exists an ice-hockey statisticians manual from NCAA where the statistics rules are the same as in the NHL (http://fs.ncaa.org/Docs/stats/Stats_Manuals/IceHockey/2021.pdf).