Hi Jane 06
The cat food and biscuits should be o.k. for them (some hogs aren’t keen on changes, so probably no point complicating things). As well access to water all day every day. I imagine they may be able to drink from your pond, but I usually leave a few water sources around the garden. Large plant saucers are ideal for that.
There’s no way of telling whether the hog will stay or not. But it’s quite likely it will continue to visit even if it moves nests. Hogs do tend to move nests from time to time – which is handy for minimising problems with external parasites. But if it moves out of the hog box it will, at least, give you the opportunity to clean it out and make it ready for a new tenant, or maybe even the same tenant again.
Good luck and happy hog watching!