Legion near Judea at time of Jesus

[Frank]

Also, if some cohorts were detached from a legion what cohorts would most likely be sent there (would it be one of the veteran cohorts like the First Cohort or a recruit cohort like the 4th Cohort), and would their pilus priors be part of the prefect's staff?

As mentioned above, the cohorts in Iudaea these times were most probably auxilia cohorts, commanded by a praefectus cohortis or a praepositus cohortis. This could be a former centurio in the early principate or an equestrian. 2nd in command was a centurio princeps, the centurio of the 1st centuria of the auxilia cohort.

A tribune just makes sense as a commander (praepositus) of a vexillatio of legionary cohorts (usually more than 1 cohort), or as a commander of a roman cohors ingenuorum or voluntariorum. But afaik there was no auxilia cohort of roman citizens in Iudaea these times.

However, there is no evidence, that a first cohort was ever used as a vexillatio. The first cohort played some role in the adminsitration of the entire legion (e.g. the princeps). So it is highly unlikely, that a first cohort was in Iudaea.

Afaik, Pontius Pilatus was a praefectus and not a procurator. The system of praesidial procurators was not fully established yet. So I guess in Iudaea you got praefecti cohortis reporting to the prefectus gentis Pontius Pilatus.

Regarding the legionary cohort mentioned above, which was perhaps deployed to Iudaea: We got no clue, who commanded a legionary cohort! Best guess is, that in case of deployment it was decided situationally. Could be a tribune, or the pilus prior was used as praepositus cohortis or any other centurio of the exercitus became the praepositus by whatever reasons.

Finally, every governor was almost fully free in composing his consilium. But it is a good guess, that the commanders of the cohorts (praefecti cohortis) were part of it; at least situationally.

PS: I forgot a 3rd option, which was possible until the Flavians: the commander of an auxilia cohort could have been a local noble. Most probably with roman citizen rights, like Arminius, but not a native roman.