This is interesting, where does this information come from?

Is the theory then that he made the deal with the Pinkertons in exchange for his freedom with the intention of becoming ‘’normal’’, and then relapsed into the life of crime?

Hiding from the law I mean, as in being an outlaw. What sense would it make for him to cut a deal with the Pinkertons, rat out the VDL gang to then just keep living the outlaw life as per usual on the run from the law and living in camps? What would he gain except for more enemies?

It is a possibility that Micah never wanted to be a ‘’normal’’ person and was the type to thrive as an outlaw, just like Dutch was. However, if that was the case it would’ve been in Micah’s best interest to work with the gang instead of against them, so that the gang would succeed instead of go down. It wouldn’t make sense for him to infiltrate the VDL gang, run with them for 6 months, rat them out to the Pinkertons (and put himself at risk in the process too, he was involved in enough ambushes/shootouts) to then go on living as an outlaw without any significant money or his freedom in return. Would he rat everyone out just because? I don’t think so, he seems like a very rational person that makes his choices based on what’s expected to be the most beneficial for himself.