Always good to start with single flavor puree - introduce one new food at a time, once a day, and maybe same item for 2-3 days. You can try these: apples, nectarines, carrot, pumpkin, sweet potato, etc. The reason for isolating the items, and using the same menu for a few days is that some food might make them bloated (cry in the evenings), some might have skin allergies, etc. So if one food makes them cry in the evening 3 days in a row, pretty safe to think that is the food to avoid for the time being.
Also, before there is the "mixed fruit/veggie" there should be pure whole food. Do not start by disguising the not so sweet food (carrot) with apples. This will make them lean toward the sweet foods. Give them a variety of sweet and non-sweet I.e. avocado, green peas and carrot, vs apples, pears, etc.
When he graduate to porridge, you can try using the same "meat" ingredient with one of the "vegetable" ingredient. Again, introduce the meat (new) ingredient one at a time. So you will have meat items: fish, pork, beef, chicken; plus any of the vege combo: spinach, broccoli, cauliflower, etc etc.
