Supplemental Work 5/3/1

Does supplemental work have to be one of the main lifts? I want to take more of a powerbuilding approach. For example, would running deadlifts at 5/3/1 and then hack squats at FSL instead of BB squats be valid?

Wendler clearly states that supplemental work can be done with “alternative” lifts and even lists some of the options. The only thing you need to do is to stick to supplemental work percentages, which means you will have to take an extra week to test TM for those lifts, and calculate percentages.