Not in general usage.
If you look them both up in a dictionary you might perhaps find a couple of additional meanings for one or the other.
I understand that "ei ddihuno" is "HIS waking" and "ei dihuno" is "HER waking". Would it be as correct to use "dihuno" in this sentence, or is there some rule whereby you must use "ddihuno"? (I am comparing this with French, where "they (100 girls)" uses the feminine verb, but "they (99 girls and 1 boy)" uses the masculine verb - if I am correctly remembering my schoolgirl French!)
Since the gender of who or what is being woken up is indeterminate, we use the masculine grammatical form in Welsh, so that is why it is Pwy gaeth ei ddihuno...?
May I check that I have understood? So it depends on your not knowing the people being woken? In an all-girls boarding house say, you would be able to correctly use the feminine form, because you know that any person woken would be a girl? The word used ("dihuno" or "ddihuno") is specific to the situation being described, not specific to the sentence itself? Thank you.
If the gender of the 'who?' is unknown or known to be mixed, use the masculine form. If the gender is known to be one or the other, then use the feminine or masculine form as appropriate.