The Strucker twins were mutants so they might've been included in the package deal with the X-men or whatever deal they worked out on the Maximoffs. Or maybe they were too minor for Marvel to care. Or maybe the Spidey deal will have them being buddy buddy from here on out. Who knows.
Not sure which is weirder, that they put a Cuckoo in the show, that they only put in one, or that they picked one of the dead ones.