I also have not encountered the word "viand" outside of our culture, maybe because, in the US for example, rice is not commonly eaten. I don't know what other rice-eating Asian cultures use as their English term for it. Most Filipinos would say "viand" if you'd ask them what "ulam" is in English.
Your second and third sentences are correct. Maybe if I used "actor-focused" instead of "subject-focused" you might have gotten the first sentence correct too. It should be:
"Sila ay mag-uulam ng adobo sa kanin"
If you'll notice, only the "ay" is added in the subject-predicate form of the sentences. All the other words remained exactly the same. What changed was the subject of each sentence. In the first one, since it is subject/actor-focused, the "doer" (sila) is the subject.
For the two other sentences that used the object-focused verbs, the "iulam" sentence had "adobo" for its subject while the "ulaman" sentence had "kanin" as its subject. "Adobo" and "kanin" are the two intrinsically related objects of the verb. That's the reason why I even enclosed in parentheses the "kanin/tinapay" phrases because even without them, the meanings of the sentences would still be understood.
The other examples may be restated in the same way.