Picture book dummy questions (to be sent to literary agent for traditional publishing)

Good day everyone!

I have written many picture book manuscripts and now deciding to illustrate my manuscripts before submitting to literary agents.

I have done hours and hours of research and cannot find a clear answer to my questions for traditional publishing.

1. I am wondering if a simple pencil can be used for the sketches or should they be in granite pencil? What do all of you use?

2. The dimensions… is that something the publisher will manage or do the specifics need to be set by the aspiring author? I see small dummies being made online. Is this permissible? Does the publisher enlarge the illustrations to the right size in the final process of editing?

3. The words of the book…. Do we put that into the dummy with photoshop etc beforehand or leave space for the editor? If we add, what font should we use for publishers, assuming this will change?

I know this is a lot of detailed questions but I would appreciate any experienced insight! The answer to these questions are holding me back.

Thank very much for your time and will appreciate your feedback. All the best!❤️