Are the Tentmakers Catholic?

If you’re referring to people whose profession is the making of tents, the Church does not exclude people on the basis of their profession, provided their profession doesn’t involve promoting and/or engaging in intrinsic moral evils. However, even then, the Church is always willing to reconcile wayward members and welcome new and repentant members, whatever their past.

If by “Tentmakers” you’re referring to the young-adult ministry that seeks to form missionary disciples, no, that is not a Catholic apostolate.

By the way, for a good Catholic apostolate that forms missionary disciples, we heartily recommend participating in or supporting otherwise the Fellowship of Catholic University Students (FOCUS).