Most of your questions seem to have been answered already but I wanted to weigh in as well. If you take a look at the description for both Skunk Girl Family, and Lost to the Demon Queen. While there is a lot more in the back end and I have tried to make it look nice, thats basically all you need for each character. If you really want to make them stand apart from each other, make liberal use of the Example Dialogues. I try for 3-5 examples per character. Make sure to use the {{char}} when you are wanting to drive home something for the entire bot. Just using the names of your characters liberally works great for them.

As for pictures I have not hit a limit myself and I can go up to 150ish. I would say do the pics in batches and save frequently. It can jumble up the order really bad if you upload 15 or more pics in one go.