A. Meatballs and Spaghetti: The Halachos of Brachos Handbook by Rabbi Yisroel Pinchos Bodner, Shlita (Feldheim p. 59), writes: If meatballs are small and eaten in the same forkful with spaghetti, one brocha, Mezonos, is made. If meatballs are eaten separately, one should make two brachos, first Mezonos on the spaghetti, and then Shehakol on the meatballs. Two brachos achronos would then, of course, follow.
B. Cholent: The Laws of Brachos by Rabbi Binyomin Forst, Shlita (Artscroll, p. 217), writes: If the cholent contains barley, beans and potatoes, and they are eaten together and not separated, only a Mezonos is required despite the fact that barley is a minor ingredient. If, however, the pieces of potato are large and are eaten separately, a Ho’adomo would be required, as well.