Question: Does the Red October not have a signal light on the periscope like the Dallas? It's a little ridiculous that they have to ping them to acknowledge them.
Answer: Red October would certainly have a signal light. If Dallas thought they were talking to the ready to defect Captain, I can't think of a more dangerous way to ask him to reply. Ordering the sonar signal certainly alerted the entire crew that something very unusual was going on. Plot error for sure.
No plot hole. Ramius explains the first and second ping to his crew as "(re)-confirming range to target." If they had seen him toggling a bunch of morse code via the signal light, they would either have recognized the morse code themselves or at a minimum wondered whom he was talking to and what about.
Chosen answer: The literal translation is "Vilnius Principal", but that doesn't sound as imposing.
Schoolmaster is correct. Nastavnik means male teacher or instructor, i.e. a schoolmaster. It does not mean "Principal/Headmaster/Head Teacher."