Decorative

You can ask for the coordinator for direct help or to find help. However, the coordinator could also be busy making sure vendors are on time. You can possibly hire decorator folks as a vendor or on your own.

You sure can. Many coordinators also offer decorating/set up services. Talk to them in advance to let them know what all your decor/set-up will entail, that way they will be able to have enough assistants with them on the wedding day. When I was a planner, I and my team often did set up.