I’m wondering if anyone can provide any insight into differences between the Theravada vinaya and the Mahayana vinaya (vinayas?). I’ve heard that Mahayana is “less strict”. Does anyone know of a good source for investigating Mahayana vinaya in English?
“Strict” is a highly subjective term. In general, I don’t think it’s really useful to generalize as to Vinaya practice in this way: different traditions tend to care about different kinds of things. Chinese Mahayanists, for example, eat a small meal in the evening, which the Theravadins don’t do. On the other hand, every Chinese monastery I have visited has been spotlessly clean—which is also Vinaya—while many Theravada monasteries are filthy. It’s best to learn from each other!
In terms of texts, there is no such thing as a “Mahayana Vinaya” or indeed a “Mahayana Sangha”. Monastics of the Central Asian traditions follow the Mulasarvastivada Vinaya, and those of the east Asian traditions follow the Dharmaguptaka Vinaya. The essential rules and procedures of these Vinayas are similar. The Mahayanist traditions did, in addition, develop traditions of interpretation and contextualization for the Vinaya, which starts in Indic texts and continues in the local traditions of China and Tibet.