Based on your guidelines and targets, here is your custom meal plan:

**Breakfast (100 Calories, 40% of 250 calories)**:
- Ostrich Meat (100g): 97 calories.
Your breakfast should be 40% of your daily calorie intake, or 100 calories. Other food items should be added if necessary to reach the calorie and nutrient targets.

**Lunch (75 Calories, 30% of 250 calories)**:
- Bream (75g): 56 Calories
- Coke Zero (300ml): 0 Calories
Your lunch should be 30% of your daily calorie intake, or 75 calories. Other food items should be added if necessary to reach the calorie and nutrient targets.

**Dinner (75 Calories, 30% of 250 calories)**:
- Country Chicken Casserole (150g): 72 Calories
Your dinner should be 30% of your daily calorie intake, or 75 calories. Other food items should be added if necessary to reach the calorie and nutrient targets.

**Grand Total:** 
This Meal plan's total calorie count amounts to 225 calories which is quite close to your daily goal of 250 calories. 

**Macronutrients:**
- Fats (154.5 Calories, 62%):  17.25g
- Carbohydrates (56 Calories, 28%): 14g  
- Proteins (14.5 Calories, 10%): 3.63g

These macros are calculated according to the average nutritional values of the listed foods, ensuring each meal's contributions towards the daily caloric and macronutrient goals are easily understood. 

**Grocery List:**
- Ostrich Meat (100g)
- Bream (75g)
- Coke Zero (300ml)
- Country Chicken Casserole (150g) 

Please note that the macronutrient targets are not being met. Additional tweaks may be required subject to your personal preferences and dietary needs.