I'm assuming that your canned salt is NaCl.
If you were to add all of your salts to the 4 gallons of strike water, and also use the 0.2 lbs acidulated malt in the mash, my sheet predicts a mash pH of 5.37. Note: that's without citric acid (which my sheet doesn't do anyway), and which it doesn't appear you'd need. FWIW, I could be wrong, but I would not expect a small amount of it to give your beer a citrus flavor. (To test that, you could take a pint of IPA, add an equivalent amount of citric acid to it, and taste.)
Then you could sparge with untreated distilled water.
Let me know if you want me to run any variations on this.
ETA: I missed that you had provided a target of 5.4-5.5. Decreasing acidulated malt to 2 ounces would change the pH prediction to 5.43.