That is indeed a flower sheath in the first picture and hopefully will see your cattelya flower. Don't be too disappointed if this first sheath doesn't produce a bloom because not all sheaths will automatically result in a bloom.
The third picture shows you how the cattleya and other sympodial orchids naturally behave - that is they grow on top of the potting medium and the roots grow down into the potting medium. Beginners ( and that includes myself when I started) tend to bury the plants too deep in the medium.
Your plants are looking good. Congrats.