Profile for Hersheyguy620

Does anyone know if there is a way to hear about performers who are making their Broadway Debuts? I'm not talking just the big stars and principal roles, I also mean people who are cast as replacements in currently running shows in all aspects, whether it be as a principal, ensemble, or swing. If anyone knows of how to keep track, please let me know!

If someone is making their Broadway Debut in a new show, is the first preview date considered the date of their debut? Or would it be opening night?