I currently use a Texas series LLC for my TX houses, and I use a FL LLC for my Florida houses; I also have an S-Corp which manages the two LLCs.

Work to manage the asset (even if you hire a property manager).Here's a quick example.

He will be a first-time landlord and I asked him if he would allow me to help him through the process of putting a tenant in place and managing it just to learn the proper flow of how it's done and to get a strong handle on the systems that will allow us to do it.

These sellers typically want a fast sale to move on with their lives and avoid ongoing conflicts.Relocating SellersPeople who need to relocate for a new job, military deployment, or other personal reasons often seek a quick sale to avoid the burden of managing a long-distance property.Inherited PropertiesHeirs who inherit a property they don't want to maintain or manage may be eager to sell quickly.

Could you recommend a reliable agent and property manager that I can work with to kick start my journey?

This is before we account for vacancy, management, capex and maintenance, etc.

What are the consequences if a BnB owner/investor (my client), decides to change hosts or self-manage in the middle of a booking?

Third, develop a property management model and plan to keep expenses low and revenue high. 

Nearly 20-year property manager here.

Something tells me you won't be working 4,060 hours to do so - 80 hours a week year round.If it is a more active rental model that it is not considered "rental" income, then you would need to put in at least 100 hours with that being more than anyone else (employees, contractors, management company, etc), or you would need to put in at least 500 hours.So your "quick" question is actually fairly complicated.