You'll need decorative items, creature comforts like books and DVDs, linens and towels (including enough for your longest anticipated stay), bathroom items like shampoo and soap and toilet paper, and a monthly budget for re-supplies of these.I'd also recommend purchasing a vacation rental insurance policy, to cover the furniture items and other things which may get damaged by a guest. 

If the Tenant claims you threw out their expensive leather couches, you can claim you showed up and it was empty just like it was supposed to be.

A person can put some rudimentary furniture in there and maybe a tv, a microwave and a portable toilet. 

When there is a flood and all of their furniture and clothes get damaged, who are they going to look to for reimbursement?

Viking appliances adorn the gourmet kitchen which features marble surfaces, custom inset furniture grade kitchen cabinetry, pot filler, wine fridge, and built-in micro/drawer.

House C, I just bought, is a < 1000 sqft beach house, it's very cute and simple, and the furniture I'm putting there will all work as furniture for a simple AirBNB/VRBO. 

Normally, I would be putting together the floor plan and purchasing furniture, but since the place is furnished and the management is staying place, not sure what else I should do right now.

They don't move furniture in and out.

Cats are based on whether or not I've got personal property in the house (i.e. upholstered furniture that Garfield would love as a scratching post) or if the unit currently has carpet in it.

If it goes wrong then sell the furniture, or only buy things you're happy to keep as spare room furnishings.There will always be people in your life telling you you're crazy for any kind of real estate investment you're going to do.