For the Blix, which has an 8 week shelf life, it's reasonable to just make 3 liters initially, then make a liter at a time as needed. This keeps the measurements simpler, avoiding fractional milliliters:
1500 ml water + 426 part A + 600 ml Part B + 45 ml additive + water to make 3L.
For the dev, with a 6 week life, making 2.9 liter total from 2.5 liters of dev replenisher will keep measurements simpler, with only part B having a fractional amount. Making 5L at a time would avoid the fractional part B, but that's a lot of developer to use in 6 weeks.
For 2L initial tank solution with starter plus 900 ml replenisher without starter:
1250 ml water + 125 ml part A + 55.5 ml part B + 125 ml part C + water to make 2.5L
Reserve 900ml for replenishment. To make the initial 2 liter tank solution with starter:
1600 ml Developer Replenisher + 350 ml water + 50 ml Starter = 2L