Last night we went to a hockey game. As you know, before every game, the national anthem is sung. They had a "choir" of young people. In this case, a single soloist would have been a really good choice. These young children weren't given a starting point and thus became a group of soloists singing at roughly the same time. Cacophony was the result. (A harsh, discordant mixture of sounds). Oh dear.
I am not a big proponent of soloists used with a choir unless of course you are singing music written with choral and solo sections such as Handel's Messiah. Some choral pieces are written with a "solo" which often sounds better with a unison section of singers. The balance is usually much better especially with amateur groups.
Please, think long and hard before insinuating soloists into a choral concert. It seems to me a, dare I say, a lazy way to fill in space. The soloist does a lot of work to prepare and leaves 3 or 4 spaces the choir doesn't need to fill. There are always exceptions of course but I firmly feel that you can create interest and variety by using various arrangements, styles, and dynamics before just throwing in a solo or two.
In a choir, you work hard to work together and create a blended, united sound. When you pull soloists from your choir, you can put that group dynamic in jeopardy. Bringing soloists from outside, can bring a host of challenges including how to work that into practice time. If your concert is a variety show, then we are talking about a whole different animal.
As I sit writing this post, I am listening to a concert by Josh Groban. As a soloist, he uses many arrangements, instruments and styles to create variety. A choir or chorus might serve as accompaniment but he is what the audience came to see.
Here Josh is singing one of my personal favourites, You Raise Me Up.
Your choir is great and with more practice will become even greater. The audience deserves their music and your best efforts and your happy faces. That of course, means you perform from memory. Yes, you CAN!!