I'm parsing this as 'adjusting coverage through layering hosts and floaters on/off', taking this to mean that in the work schedule these two categories of personnel are 'overlain' (or not) from time to time, though whether this is relative to each other or to other shopfloor staff I cannot say.

I'm also assuming that by 'host' they mean something similar to what I know as 'hôtesse d'accueil': that is the title of one of my step-daughters, i.e. the person by the entrance to the store who lets you out without a purchase by pressing a button to unlock the gate (amongst a host (!) of other responsibilties). I cannot say I have ever seen this post occupied by a male employee. My step-daughter has irregular hours, being what I take to mean being "layered off" during the hours of low footfall and "layered back on" when footfall is high.

"A Retail Host/Hostess portrays friendliness, excellent customer service, and high standards while assisting customers as they shop within our venue’s merchandise stores. The Retail Host/Hostess also greets customers upon arrival, answers questions related to the merchandise and store policies, and helps locate items. A Retail Host/Hostess is responsible for processing payments and keeping the sales floor neat and well-stocked. The goal is to accelerate our business development by providing customers with a memorable experience."

I don't know the term for floater, i.e. someone in a store who is not specialized in a given field by who can 'float' from one section to another ane be knowledgeable in them all. 'Vendeur polyvalent' is a possibility but I'll get back to you on that once I've contacted said step-daughter.