"restaurant" has 1 or 2 morphemes?
Solution 1:
Restaurant has three morphemes: it is the participle (–ant) of a French verb, whose Latin ancestor added a prefix re– to the root staur; the Proto-Indo-European ancestor of this root is reconstructed as steh₂u–ro– (a suffixed variant of steh₂), so maybe I should say four morphemes, though I have no idea what the –ro– contributes to the meaning.
None of this helps you know whether the syllable break in English pronunciation is re-stau or res-tau.