Very punctual hedgehog you have there! Datewise, at least. I always think last year’s hoglets look bigger when they come back. Am never sure whether it is just because I am remembering them when they were younger. I expect some more will come when they find the scent of the first one. At least one of my last year’s regular visitors has not returned and I see from my last year’s notes that she didn’t appear until later in May and then came almost every evening. A lot of them are a bit distracted at the moment, boys chasing girls and girls looking for boys! Sometimes a hedgehog arrives here and dashes off again without having time to eat anything!
I think a few mealworms is ok, as long as it isn’t too many. I think the main problems arise when people feed loads of mealworms/sunflower hearts/, etc. to the exclusion of anything else. I usually give them a few, but tend to cut them out when the hoglets are around, as apparently they are most at risk of becoming addicted to them.
I wouldn’t worry too much about trying out different hog foods, if you have found something they like. I don’t think they really like change too much and as long as it is a good hedgehog food, it should be fine for them.