Doing some OOB research. >>36415 lists the 2nd Infantry as having two battalions but elsewhere mentions it only had one. I looked up the source (Army Reserved Bulletin 11-C, 1970) in the National Archives and indeed it's only one. But there's more, it breaks down to the company level. For instance, the Infantry-School Regiment had:
Commander & staff
Command company
Services company
Hvy mortar company
Tank company
x2 Infantry battalion
Commander & staff
Command company
x3 Fusilier company
Hvy weapons company

Most others have no heavy mortars and merge command and services companies. The number of fusilier companies per battalion varies, two-battalion regiments often have two-fusilier battalions, so those are a better yardstick for comparison.

The Tiradentes Detachment had 8 (Army) and 6 (Police).

1st Caçadores: 2, possibly only one at the frontline.