Talk about things. Find out what everybody's concerns are. Once you do that, have prayer sessions before you practice.
Let God fight the battle. Let God get your choir excited about singing His praises again. Do everything you can to get into His presence before you rehearse.
This has helped our choir. I know it will help yours. The devil can steal the joy from your choir... the good news is... you can get it back!
God bless,
Eggs