Kettle Souring -- What did I do wrong?

First run of my new electric brewery system, and my aim was to make a 10 gallon sour (aimed at a Berliner).

Note that I only have distilled/purified water here, as the tap water is not safe in my country. I added: +1tsp Citric acid +2g Baking soda +9g CaCl +9g MgSO4 +9g Gypsum

I decided that instead of making 10 gallons of a sour beer, i'd split it off with 5 gallons into a keg and 5 gallons soured then kegged.

Reached boiling point, added 1oz of Citra (mistake #1? but it ended up being only ~13IBUs, 1oz of Citra in 11 gallons should be a drop in the bucket), 20 drops of fermcap (2 drops / gallon) (mistake #2? Does fermcap kill lacto?) , and finished off the 15 minute boil. Ended up with 11 gallons of wort at 1.031.

Transferred 5 gallons to a keg, cooled the remaining 6 gallons to to ~46C or ~115F (per recommendation from guy at White Labs in San Diego), pitched WLP677 L. Debruckii (use by date was 2/28, so it was ~2 weeks past use by. Not sure if that meant it was dead or not), and held at 46C for 48 hours (using a small mag drive pump recirculating, but the discharge of the pump is under the liquid level, so no splashing. Did this mainly for temperature control purposes. Mistake #3?). No pH change (using strips) and no sourness to taste. I then re-checked my notes and saw that the temperature should have been 109-112F per his recommendation, so I reduced temp down to 43.5C -- thinking I had another Lacto culture to pitch. Ran up to the fridge and found I didn't. I ran to the store and found Yakult Live, which has L. Casei in it. Pitched 5 100mL bottles and held at 43.5C for 24 hours. No change at all.

Began research and saw some posts saying that the temperature was too high, and needs to be reduced to ~37C and it is possible my pH was too high (hovering at 6 per the strips). I dropped to 37C and added 5 tbsp of Citric Acid in an attempt to lower the pH and pitched 5 more bottles of Yakult (total 1L of Yakult in 6 gallons).

Returned 24 hours later, and the same -- no pH change and no sourness to taste. So -- what the hell? Why can't I get anything to start growing in there? I have to leave the country for a week and I am not going to let this recirculate for that long so I plan to keg today and say fuck it, hope it turns out still drinkable as some lame wheat.

Can anyone help me figure out why I can't get the sour going? Everyone online says when pitching lacto, they have tangible results in 24 hours, and usually a pH of ~3 by 48 hours. I am still stuck at pH 6.