Like in the USA, in the beginning the Beatles' albums weren't the original British releases: the first two albums were compilations, A Hard Days Night had its title and cover changed, Help! features an altered cover and different tracks, and Beatles For Sale was replaced by the album The Beatles, which had almost the same tracks, in a different cover. The original albums were eventually released in 1975, then these "non-UK" releases were discontinued. The exception is the "translated" A Hard Days' Night, which was the standard until the remastered reissue.
After 1966, the British schedule was followed, only with some delay.
In some cases, an album issued in the UK at the end of the year was released
in Brazil in the beginning of the following year, so some release years
are different.
All these albums were released originally only on vinyl LP.
I've heard rumours about a Magical Mystery Tour soundtrack album being issued that time, an instrumental album like the B-side of Yellow Submarine. But if this album existed, it could not fit in the Beatles catalog as Sgt. Pepper's is BTX 1004 and the "White Album" is BTX 1005/6.
Until the early 70's, there were separate mono and stereo versions as
in the UK. Stereo versions started with Revolver, in 1966, being
the first albums (up to and including Rubber Soul) originally issued
only in mono.
It seems that Odeon received only one master - stereo or mono - of the
songs. Songs released originally in mono (the first albums and all
singles) never got true stereo versions
(only mock stereo), and the others had the mono version combined from
stereo instead of the original mono mixes.
Stereo versions of the "mono" tracks appeared on the
compilations and late issues,
(whose masters were sent from UK and US instead of being
assembled in Brazil).
But it seems that there was never A Hard Day's Night in stereo,
and Rubber Soul was issued in stereo only in the
remastered collection.
At the beginning of the 70's, stereo records became playable on mono turntables, then mono records were discontinued and all later albums were issued only in stereo (or mock stereo).
As far as I know, the packaging of LPs reproduce the originals fairly
well, including inserts, cutouts, etc. All sleeve notes (except on Let
It Be) and most of the credits were translated into Portuguese.
Also, until the early 70's the LPs (as all Odeon ones) were packaged in
a plastic cover, patented by Odeon and never used by other companies,
and the stereo versions had an indicative
triangular sticker on the upper left corner. Only the White Album doesn't
have plastic cover or sticker, reproducing the original even better.
In the 70's when the plastic cover was abandoned and regular cardboard
sleeves were adopted for all albums.
Cassettes were released in the middle 70's. As usual in Brazil, they had poor packaging: on the front, the LP cover, on a white background with the word "ESTÉREO" in huge letters on top and the track list on the bottom; inside, the track list with composers' names. All cassettes had similar packaging.