Private teachers and choir directors know that confidence takes time. The singer, besides learning new material, is introduced to concepts that feel "different" (opening your mouth while pronouncing the "e" vowel, to name just one, and opening your mouth to sing, period, another, and pronouncing clear consonants instead of the traditional muddy stream of sounds). The wise student says "I may feel like an idiot doing this, but the teacher has a plan and a reason for what she is doing with my voice."
Those who volunteer for worship teams generally have a measure of confidence already -- thousands who could be wonderful worship team singers don't, because of nerves, worry and baggage. Congratulations to you! You're willing, and want to overcome.
As to overcoming fear, I myself like to think of singing for just one person who (in my mind) needs to hear the song, or will be blessed through it. I like to look directly at people, in the eyes, when I sing -- it wakes them up, and helps overcome the fear of masses of people. Others may be terrified by this personal approach, and resort to looking just over the heads of everybody, so they still appear to be focused on the congregation. Some like to focus on "the idea of the song" so strongly that the people fade away in light of the message that is given. You'll most likely come up with your own way; and other responders and friends can help you.
Being able to confidently sing a high note (which also takes time) is a valuable asset to a worship team member, though few songs today have any kind of high range -- but when the time comes to "wail", you'll be there. If your training is purely classical, you may want to augment it with study of contemporary singers, just y listening on YouTube, etc.
"pronouncing clear consonants instead of the traditional muddy stream of sounds"
Not if you follow the Muddy Waters school of singing!
Just googled Muddy Waters -- enjoyed him tremendously! Though his name surely doesn't have anything to do with his enunciation, I did find it almost impossible to understand very many words at all, because his regional dialect is so different from my own. But he connects on an emotional and heart-level.
Now if I listened to a lot of these deep-Southern singers, I would begin to hear the subtleties that bring out meaning. At school, I always have to ask the students what a rock song was about, because I just can't pick out the words from this mass of clanging and twanging instruments and stretched-and-pulled manner of pronouncing the words; but if I listened to it every day, I'd develop the ear (takes a lot of discipline to absorb styles). High-schoolers amaze me -- they not only can understand the words of the songs they hear on the radio, they can understand each other talking, even when twenty are talking at the same time, whereas I have to wave my arms and ask for quiet when there's a question.
Yet he's quite a capitalist. I just learned he is still alive (Carlos, not Che), and charges 79,00 euros ($120) for a gig - per customer.
But consider the impact on a post-college organist whose world consisted of Bach, Beethoven and Louis Vierne, whose total sole experience in rock was watching "Woodstock" at the base theatre, and buying an album of Chicago simply because I was born there.
I don't believe you ever full get of nerves. Your anxiety will get shorter, for example you may only feel the rush of nerves right before you sing and not all morning long. :) Here are a few tips:
1. Know your instrument and only bring to the stage what you know you can do. If the high notes are uncomfortable off stage, your nerves on stage will make you have even less control of those high notes. Make sure you are comfortable with the notes and have them effortlessly.
2. If you are too challenged vocally on the platform it will show in your face. You need to be extremely comfortable with the song in order to deliver it effectively.....eye contact, smile, worship.
3. Don't be married to the original version. If you can't hit some notes, find an alternate note or change the style so you just touch the note and backoff it or trill down (quick notes to a lower note...they do this a lot in gospel.) If you must follow the original version, lower the key to something comfortable. I'm assuming you are singing the songs you listed for training purposes and that is not the type of solo song you will be singing.
4. The most important thing about singing a solo is not the notes but the delivery. How you express the words in the song. How real it is to you will make all the difference in the world. This is when you step out from just singing to ministering, which should be the goal of any singer. :)
Hope this helps.