You can use any stabilizer / final rinse sold for E-6 as a substitute for a C-41 stabilizer / final rinse.

So if you drop or spill etc. the stabilizer in your Digibase kit you can use any stabilizer for E-6 instead of chasing that specific final rinse. If you have some final rinse for E-6 in larger quantity or easier sourcing you can use that and avoid rolling the tank on the floor if this poses a problem.

As far as rinsing is concerned if your local tap water is of normal quality it should be fine for all washes. Distilled water is useful to dilute the stabilizer / final rinse because it helps you avoid water marks on the film after drying, but for all other stages (dilution or washing) does not give any advantage over normal quality tap water.