My cat was throwing up her previous food,chicken,so I tried a different protein. She can eat anything else. Since I found out through trial and error I now know what I can feed her. She cannot eat pate because she eats too fast and licks her food, so only minced and an elevated bowl.
What was she eating before?
It might be fine to mix a good with similar ingredients or limited ones.
Magnus was on Purina EN for awhile for tummy issues. We then mixed with Purina chicken and rice as it was similar. Now he eats a few similar food with chicken as the protein and eventually he could have some lamb, tuna and salmon as long as the other ingredients were similar.
I'm not familiar with Sheeba other than it has a few lines with milk and cheese in it. Steer clear of those. You'll want a very plain food like Iams perfect portions kitten food.