I don't think a vacuum is cheeky, if you have children coming back from the beach there is probably going to be sand.
When booking maybe give options for the 'welcome' pack eg I don't drink milk and I love proper coffee. My (now deceased) mother would need tea bags - the cheaper the better and milk.
A decent knife in the kitchen, just one good cook's knife is great, more than one is a bonus.
I wouldn't include bikes as there are implications with insurance and maintenance, it could literally be a liability.
Wi fi is a must these days. Also some plug sockets with USB slots for charging.
Information about the local area, nearest chippy, take away, walk in clinic, chemist, corner shop. Local places you know about but others may not eg does a local farm sell produce to the public.
High chair, baby gates and a cot if you are marketing to a family. If you have blinds don't have the ones with strings, people don't always wrap them up and they are a hazard for young children.
A couple of fans, AC if possible, even a portable unit - but leave instructions.
Also instructions for anything electrical washer, dish washer, microwave.
Bedside lamp, bright enough to read by. Actually in my spare room / office the bedside lamp has different brightness, you just tap the base and it comes on and then tap again to dim it, dim it further, off - so could be left on low for a child who doesn't like the dark.
An emergency box, or shelf in a cupboard with a torch, candles matches, first aid kit. In an upper cupboard so toddlers can't get in.