The donor must be willing to undergo monitoring of response to the medications, including blood testing, etc. First of all, there is no information that I am aware of for hair color, eye color or a specific gene that controls those factors. Secondly, there is what is known as preimplantation genetic diagnosis. A cell is taken from the embryo and evaluated. There is an ethical issue surrounding this issue.
Frozen sperm can preserve fertility, generally speaking.
We recommend freezing as many specimens as possible. With this technique, we can get fertilization by injecting a single sperm into an egg. You only need one sperm per egg with this procedure. With one specimen, you could literally do hundreds of procedures. Sperm is generally frozen at minus 196 degrees Centigrade in nitrogen and can still be viable for many years.