I only feed one or two hornworms at once. They are quite soft and not scary at all. They are full of liquid though so they can be messy at times when bitten. No need to cut anything just offer one and see how well they get chewed up. If they seem to big to handle easily offer smaller ones instead.
Black soldier fly larvae is the name of the bug. ReptiWorm, CalciWorm, and PhoenixWorm are brand names for the same bug.