Always tricky, these indefinite relatives. This one even more so (and illustrative) because the writer truncated the clause, i.e. the clause isn’t stated explicitly but is rather implied: ‘to whomever else [wanted them]’. And therein lies the problem. Just because the clause isn’t explicitly stated doesn’t mean the grammar doesn’t apply. The ‘whom’ in ‘whomever’ is there because of the ‘to’. But ultimately the ‘to’ is irrelevant to the ‘whomever’. The whole clause is the object of ‘to’; the grammar of ‘whomever’ is beholden to its clause rather than to ‘to’. And because it is the subject, albeit of an implied clause, though a subject nonetheless, it should ‘whoever’ rather than ‘whomever’.