I have a group (40-50) seniors who would like to visit. Are dedicated guides possible? How many per group? Dining for a large lunch group? Can we get publications describing the museum and exhibits in advance? Is there a cost for large groups?

You should definitely call the museum directly and ask them for more information. These types of questions are not very good for asking on Google Maps... The types of questions we are good at answering is just basic info

Please call the museum, they may be able to accommodate your group better. There's no cost for admissions but there is one for guided tours, I don't have the answer for a large group. There's room for lunch for large groups.

The museum is free unless you buy tickets for special venues, be prepared to wait, I went at 10 am on a Friday and at 1045 I was still not inside

I could inquire about this info by calling the Museum itself

Not totally sure about costs for large groups, but I doubt if they charge extra. I would suggest checking out their website in more detail and maybe sending an email inquiry. I found the people working at the museum to be very nice and helpful.