If you can’t have a not Frum coach how can you have not Frum teachers or go to a historical site and listen to the guide? (Though this is probably one reason you don’t want kids to learn secular studies). Maybe weighing the downside of interacting at a young age which is zero against creating positive relationships which payoff in the future the Derech is clear. Unless you believe “They hate us because they hate us” or they’re “jealous” of us; creating trust, understanding and friendship at a young age goes a long way toward things being easier in the future.
