Before food trackers, there was Google. I still use it (or my own excel sheet) more than trackers.
-Google "calories in name of food"
-if the amount is given in grams, 28.3 grams = 1 oz
-try to use the uncooked weight because cooking changes the weight by dehydrating the water out of food and we all cook things differently
-stuff in cans should have the calories on the can
Once you have total calories for your whole preparation, divide it by the number of meals/snacks it's going to make. In your above example, you're going to make four portions. So, total # of calories divided by four = calories per portion. Even if you don't make each portion exact, just make sure that the four days equal the total.
Example: You make something that has 1000 calories and it's 4 portions. Each portion is 250 calories. You eyeball the portions while counting 250 calories each time you eat it. You notice on day four that it looks larger than the other three portions. It doesn't matter. Still count it as 250. Total for 4 days is 1000 and while each day might not be exactly correct, it's calories over time.
Oops, I read every sentence in your post except the last:
Should I add up the calories of the individual ingredients via something like MFP, then divide the number by 4 and call it good?
"Right is right, even if no one is doing it; wrong is wrong, even if everyone is doing it." - St. Augustine