I am a minister and I like to sing. I would go with number four as well. If the minister is secure with himself/herself then it is OK to stop and correct.

Rehearsal is good as well. A little comfort level with each other is an asset!

Are there others to lead the singing more musical than the minister?. The more lay leadership the better, I figure.

I would like a good guitarist in musical leadership in my church if all else fails.