Support needed on basic understanding Generative AI

Hello I am trying to understand Generative AI and the usage for business. I have some questions someone here can answer potentially. I tried to go to different places and a week of research and even asking ChatGPT, but it is difficult to find answers to below questions, so any help is appreciated.

First question:

Can some one explain me the difference between Training a model, fine tuning a model and embedding a model. When would a business use embedding vs training vs fine tuning?

Second question:

How to host and interact with a model? I see that Generative AI frameworks is the way to go, but it is quite difficult to understand which options are available and which models do they work with, what features do they offer and what is the pricing. Can you please support with this?

Third question:

Do you know where I can find costs for training a model or embedding or finetuning - especially for non OpenAI models (open source)?

Fourth question:

Is there an exhaustive list of LLMs that are classified per function (image, text, audio, 3D …) and open source vs proprietary.

Even if you can answer partially, please feel free to do so.

Thank you.