Hi – great questions!
We don’t currently ship with a Hebrew translation. All our language files are actually the result of community volunteers who have contributed their time and knowledge – and we are delighted to offer a free license to anyone who can provide complete translations in a new language (for both The Events Calendar and Events Calendar PRO):
tri.be/support/forums/topic/translations-getting-started
At this time we don’t natively support the Jewish calendar, however, and I suspect that adding such support would require a considerable amount of re-engineering – however, we’d happily consider it and you can post a feature request if you’d like to see this – that way others can show their support, giving us a metric of how much demand exists for this.
I hope that answers your questions but please don’t hesitate to let me know if there is anything else we can assist with.