The WTS is careful in print to say "paid clergy" which implies they have an unpaid clergy. A so-called legal approach quibbling about words by the WTS to CTA (plural of CYA). As to the mediator article in 1989, I always ask, is there some WT info that is more recent that adjusts or clarifies that teaching?
The current Insight book says about Mediator, considered up-to-date info for jws to use for research (also cited in the same place as the 1989 article: "Those for Whom Christ Is Mediator. The apostle Paul declares that there is “one mediator between God and men, a man, Christ Jesus, who gave himself a corresponding ransom for all”—for both Jews and Gentiles. (1Ti 2:5, 6) He mediates the new covenant between God and those taken into the new covenant, the congregation of spiritual Israel. (Heb 8:10-13; 12:24; Eph 5:25-27) Christ became Mediator in order that the ones called “might receive the promise of the everlasting inheritance” (Heb 9:15); he assists, not the angels, but “Abraham’s seed.” (Heb 2:16) He assists those who are to be brought into the new covenant to be ‘adopted’ into Jehovah’s household of spiritual sons; these eventually will be in heaven as Christ’s brothers, becoming a part with him of the seed of Abraham. (Ro 8:15-17, 23-25; Ga 3:29) He has transmitted to them the promised holy spirit, with which spirit they are sealed and are given a token of what is to come, their heavenly inheritance. (2Co 5:5; Eph 1:13, 14) The total number of those who are finally and permanently sealed is revealed in Revelation 7:4-8 as 144,000." And in 2008, the WT says "What does Jesus’ role as Mediator involve? Well, Jehovah applies the value of Jesus’ blood to those being brought into the new covenant. In this way, Jehovah legally credits them with righteousness. (Rom. 3:24; Heb. 9:15) God can then take them into the new covenant with the prospect of their becoming heavenly king-priests! As their Mediator, Jesus assists them in maintaining a clean standing before God.—Heb. 2:16."