Normal
I can't comment on the Hotel Galvez as I did not stay there. 4pm is the departure time. You have to be checked in at least 60 minutes prior and some cruise lines say 90 minutes, which means you should get there no later than 2pm or risk being denied boarding. There were seats when I was there, but I boarded the Royal Caribbean ship. Nonetheless, all the waiting areas I have been to (I've been on 18 cruises) have seats in the boarding area. And yes, there is a security check just like at the airport, except you don't have to take off your shoes.