If you see a current copyright notice on the music you intend to live-stream or print, you will need to report it to the appropriate licensing entity. This includes the following:
The publishers of your hymnals has gotten permission from the publisher of the music in the hymnals to reprint the music. This does NOT give you permission to reprint the music. If you have a OneLicense license, you will have permission to print most of the music in the hymnals printed by GIA, OCP, and WLP. If there is music in the hymnal that you want to use, but it is not published by one of those three publishers, you will need to go onto OneLicense and check to see if it is included in the music they represent. If it is not included on their website, you will need to contact the publisher and get permission to reprint the music. This may cost quite a bit. I think the last time I had to get permission to print a song, it was about $50 for each time I used it. This could get quite expensive if you are using music that is not included in OneLicense.
Purchasing the music gives you permission to use the music in a private (i.e. Mass) setting, but does not necessarily give you permission to reprint the words or music in a worship aid, printed or online. There is an exception to this. Sometimes, a publisher will print a version on or around the back page of the choral piece that allows you to print the refrain or the whole song for the congregation. You can print whatever the publisher allows you to print without having to report it.
If you are live-streaming Mass, you will need to report any copyrighted music, including instrumental and choral music that are not being printed in the worship aid. This is because it is being streamed to a public audience instead of a private Mass. The recording of the live-stream may be kept on your website, Facebook page, Youtube, etc., as long as you have a current license with the entity who holds the copyright. Once your live-streaming license is not in effect, you must pull the recordings from the web.
If you are recording a CD or DVD of your choir for any purpose, you have to get permission from the publisher of the music. They will charge you for the right to record and give away or sell the CD or DVD. This is important to remember.