Amazon.com: Customer reviews: Simpleaf Flushable Wet Wipes: Eco-Friendly, Thick, Effective, Paraben and Alcohol Free, Hypoallergenic and Safe for Sensitive Skin, Vitamin E (1 pack of 30 counts Singles and 3 pack of 20 counts pack)
It's more expensive than standard flushable wipes but if you want eco-friendly then this is one of the two cheapest I've found.
It's as soft as any other flushable wipe but not as soft as baby wipes.
It doesn't say it's a sensitive formula but I'm fairly sensitive and I didn't experience any stinging or burning while using it.
Even though it should be sensitive enough for children I don't recommend it for potty training. The wipes can be very difficult to get out of the package without ripping, especially when the package is fuller.