First understand that he Divine Universe does not place more importance on Teacher, Guide, or student. We are all equal beings. Whether it is a teacher in the physical reality or a teacher in the spiritual reality, it is not the same as a guide. One can be a guide in the physical reality or one can have a guide in the spiritual reality.
A Guide is like having an expert witness. Think of it as a court room. You need expert advice on a specific piece of evidence. The expert witness gives testimony only relevant to that specific piece of evidence. A Guide is an expert in a particular field that gives you guidance on a specific area of your journey. In the physical reality, I am a Guide for the Waiest Mental Martial Arts. I am not an expert in Karate; although that is part of martial arts. I specialize in Mental Martial Arts only.
In addition, many times animals are called animal guides for the simple reason they have specific messages or medicine for you to breathe in and use on your journey at that moment. Guides can come and go on your journey. Think of a guide that travels with you when you are exploring the wild or on a safari. They are with you for that journey and then you part ways to go on new adventures.
A Teacher is more personal. They can be spiritual teachers that are not in this reality. However, with a teacher we, as human beings, develop a personal relationship with. They may be a teacher of life, a teacher of a specific aspect of life, or they could be a teacher of what not to do. They come in many forms. A teacher will always show you choices, never make choices for you. A teacher will always reveal aspects of self that we might not wish to see.
Although the student may have developed a personal relationship with a teacher, a teacher will be able to act as a sacred witness and share clarity. They will answer questions, but you must ask the question first. That is really the first action of free will. You must make the choice to ask. Teachers will assist learning but not learn lessons for you. A teacher can help see the reaction to actions and reveal where needs to be healed.