Providing cities for the priests and Levites required a shared effort from the various Israelite tribes. To complete the historical record, a summary groups together the specific tribes that contributed portions of their own land to support the descendants of Aaron. This account fills in missing details from earlier records and organizes the final list of contributors. Notably, the tribes of Judah and Simeon were absent from the initial descriptions of the city distribution. Their inclusion here reveals that the entire catalog of cities detailed previously was, in fact, provided by them [רש״י]. Because Simeon needed to be formally added to the record, the opportunity is taken to list all the partnering tribes together [מצודת דוד].
There is no specific identification of exactly which cities came from Simeon. This is because Simeon's land was entirely enclosed within the borders of Judah. As a result, any contribution from Simeon was naturally included within the cities given by Judah [רש״י, ביאור שטיינזלץ]. The tribe of Benjamin is also listed among the contributors. Although Benjamin’s participation was already recorded earlier, the tribe is mentioned again to highlight its full and equal partnership with Judah and Simeon in providing cities for the descendants of Aaron [רש״י].
Finally, although the act of naming these cities is phrased in the future tense, the primary approach among commentators is that this actually refers to the past. It serves to confirm that these are the exact same cities whose names were already clearly identified and detailed in the preceding records.