H jay2020, I believe that alcohol denatures the enzyme so adding pectic enzyme after you have pitched (added) the yeast means that you are inhibiting the action of the enzyme and at best you need to add far more enzyme than would if you add the enzyme 12- 24 hours before you pitch the yeast. Indeed, if you are using crushed fruit, pectic enzyme will help with the extraction of the juice.
But I have to suggest that if your recipe calls for these ingredients close to the order in which you provide them I would very strongly suspect that the creator of the recipe either has no idea what they are doing or they are recreating something they did completely out of order and which may have no relationship to the actual fruit that you have to hand. Here's why:
1. You would add Campden tablets to inhibit wild or indigenous yeast. The SO2 gas that kills the indigenous yeast needs time to dissipate so you add this to a wide open bucket (or carboy WITHOUT any bung and airlock!) with the fruit or juice and don't add yeast for another 24 hours. This to allow the gas to blow off.
2. Adding nutrient before the yeast has begun to actively ferment may feed any bacteria that you have not removed with your sanitizing protocol. Once the billions of yeast cells take off they will overpower any bacterial activity creating an environment that favors the specific yeast cells but if you fail to pitch the yeast using best practices those bacteria that you have gorged with the nutrients may add flavors that you don't want. Me? I would add nutrient 24 hours after you pitch the yeast.
3. How do you know that your wine NEEDS acid. Adding acid before you taste the wine is like drowning a dish in salt before you tasted to determine whether the chef (or cook) forgot to add salt when cooking. And then the idea of adding acid blend rather than a specific acid that is better aligned with the fruit you are fermenting or the flavors you prefer in a wine may be an "easy" cop out but apples have malic, grapes, tartaric and citrus fruit, citric acids. Is there a good reason to add a blend that may distort the acids normally found in the fruit you are fermenting? Taste the wine. It won't do you any harm and you can tell after active fermentation has ended whether the wine tastes bright enough because it has enough acidity or tastes dull because it has too little acidity. Technically, if you are measuring the amount of acid you are looking for about 6g/L but your tongue is a good tool to determine whether there is enough acidity in the wine as far as taste goes. The 6g/L is a measure of the TA. pH is about the strength of the acids in the wine and you may want to know that to determine how much free SO2 to add each time you rack or when you bottle. TA is about the quantity of acids, pH is a measure of the strength of the acids present. Malic is stronger than lactic.
