Good evening Greg and welcome to the Events Calendar forum!
Thank you for your interest in our products.
We’ll be glad to answer your questions.
1. Does Events Calendar Pro support multiple venues in a single calendar?
Absolutely, as many venues as you want.
2. Does ECP allow for calendar submissions by the general public with the ability to moderate those submissions before addition?
Actually, ECP does not provide that functionality, but our Community Events add-on (which works great with ECP) allows you to do exactly that: https://theeventscalendar.com/product/wordpress-community-events/
Let me know if that helps.
Have a great day!
Geoff B.