Re: Terminology - Kyudansha?
"Deshi" is commonly used in traditional contexts, and implies one has attached oneself to one particular teacher for instruction. It's not commonly used in modern budo, where people tend to belong to organizations rather than learn at the feet of one particular teacher. It's still used in koryu, by which I mean not just bujutsu but also tea, ikebana, and similar traditional schools where there's a transmission in a lineage. Also in sumo. By far the most common place for regular folks to hear the word "deshi" is in comic-entertainer contexts (owarai). There, it is still common for an aspiring comedian to ask one particular veteran rakugoka or manzai-shi to train them in the art of comedy. They are considered and refer to themselves as "deshi" of that particular veteran.
There is a trend of older words such as "deshi", "monjin" or "monkasei" falling out of use. I was recently on TV during a short segment on our school, and I was captioned as "Amerika-jin seito". "Seito" is a common word to mean "student", but usually used in contexts of, say, jr. and sr. high schools, cram schools, cooking schools, things like that. "Monkasei" or "deshi" would probably have been more appropriate, but there was a certain dumbing down in effect.
Back to the original poster's question, "kyudansha" is a term to describe the general population of students of kyu and dan rank, and not appropriate for describing one person.