Welcome to the Forum!
Glad to hear you have hogs there.
They don’t always hibernate if there is food available. It probably is quite unusual, but there are always some who don’t hibernate and it isn’t a problem if they can get food and water and shelter.
I don’t imagine urban hogs are very much different from rural ones, although there are always hogs who have their own different habits and it may be warmer in urban areas.
Re. Feeding. Mealworms only is not a good idea. They love them and tend to become addicted to them and eat them in preference to other things, but they are not very nutritious for them. It is best to get one of the many hedgehog foods which are now available, either in pet shops or by mail order, or cat or dog food, meat varieties – not fish – either wet food or kitten biscuits. Mealworms are ok in small amounts, but should be treated as more of a snack, or a garnish. You may find the hogs there might not be keen to eat anything else if they have been feeding off mainly mealworms, but it would be a good idea to introduce some hog/cat food gradually. Water is very important, especially if you are feeding dry food. Hedgehogs do tend to drink quite a lot. You might need to experiment to find out what food foxes don’t eat. I imagine they would eat cat/dog food.
The gestation period in hedgehogs is about 4.5 weeks, but can be variable. Most hoglets are probably not born until June or July, but if it is a male and female visiting there, they may produce youngsters earlier – you never know! You don’t need to worry about getting anything different for the hoglets if/when they arrive. Mum will feed and look after them until they are able to eat normal hog food.
The cheapest food, is probably to try to improve the habitat in your garden and try to encourage other people in the area to do likewise – so that the hogs can find their own natural food. And, of course, link the gardens. There are lots of tips on this site.