I think you have hit on one major inconsistency of the WT doctrine. In the NT baptism and the Eucharist work as two complementary symbols (in the broadest sense of the term) of the same "thing" -- especially, in the Pauline texts, symbols of union with Christ's death and resurrection, making one a member of Christ's "body" (e.g. Romans 6:1ff). Imposing one and denying the other to the same people simply makes no sense from a scriptural perspective.
It is all the more visible as the WT, afaik, never claimed that the baptism of the so-called "other sheep" was another baptism than the one Christian baptism (cf. Ephesians 4:4ff) which the Gospels and Acts oppose to John's baptism.