Yup, don’t give them sunflower hearts! Not good for them but like bad children they’ll eat them anyway. Proper hedgehog food or cat food (Non fish, non gravy) plus water, lots of.
If there’s manic nest building going on in the morning then you probably have a pregnant girlie. Building nests for babies is very much a last minute exercise so she’ll be about to give birth any day now. DON’T disturb the nest, at all!
Welcome to your new addiction!