From my year ago experience at Cancun when the process wasn't noticeably different from the experience of entering the USA with Global Entry, I would say nothing additional like Viajero Confiable was needed.

When I was entering Mexico at Mexico City earlier this month, I didn't see anything associated with Viajero Confiable which doesn't mean there wasn't anything like that. I saw only two options - Mexican citizens were sent to the kiosks and all the foreigners were sent to the human officers. No special options for USA and Canadian citizens like a year ago at Cancun. But I must say the line to human officers was faster than I thought it would be and taking this into account, I think I wouldn't want to apply for Viajero Confiable to speed up what was already fast. My conversation with the officer took us less than a minute, for example, and the main question was how to say "goodbye" in my first language which was determined by the birth country in my U.S. passport.