Could model ever be a "de" word, to indicate the possibility of a male model? Or is "het model" for male and female models?
I'm no expert, but I think "model" is always a "het" word, just like "de man" and "de vrouw" are always "de" words, but it becomes a "de" word when it is made plural.
Would "Het model verkleedt zich" also be correct?
Hmm not sure. "Zich verkleden" usually has the connotation of dressing up in a silly costume.
Is "om" necessary in this case?
The sentence sounds incomplete without the "om". "Het model kleedt zich aan" means "the model is getting dressed". "Het model kleedt zich om" means "The model is changing her clothes".
Is om in this sentence simply part of the verb infinitive (and thus omkleden)?