I have orthotics in my running shoes, should I use orthotics also in my skates? Can I use the same orthotics? Should I choose my skates one size bigger to make sure the orthotics can fit?

You should check with a medical professional regarding orthotics. Shoes and skates have different roles and so orthotics cannot be swapped. If you already have skate orthotics, please bring them to your fitting. If not, size without orthotics. Your medical professional can then create orthotics for your skates. In any case, the size of the skates must be the correct one for the length of the feet and not one size more.