Going Through Family Collection

Do these have any value or just common stamps?

Mostly common, but the 2p from South Australia should be checked for perfs and watermark. If perf 10 and watermark 70, would be a decent value ($40.00 US in my 2013 Classsic catalog. ) Good luck!

Here is another I thought was interesting. It's cancelled with what looks like "100"

That number in the cancel identifies the town it was used in. The knowable folks on the Australia board will probably know where it came from. Some of those numbers are scarce. Interesting to know, either way.

This is Kochchi 1923 On CGS ovpt. on 1923 8P Ramavarma XVI
(1858–1932) sepia official stamp (SG O12) with SG type O3 On
CGS overprint denoting On Cochin (Anglicized
corrupted version of Kochchi) Government Service.

The unoverprinted base stamp is Kochchi 1923 8P Ramavarma XVI
(1858–1932) sepia (SG 38) with comb perf.13.6, printed in recess in
sheets of 48 (8×6) by Perkins, Bacon and Company Limited, London,
England on machine-made softer paper having horizontal mesh with
umbrella watermark.

The On CGS ovpt. with straight-backed C variation occurs
in position R3/1(17) in the sheet.

Vignette: The stamp features Ramavarma XVI (1858–1932), ruler
of Kochchi (1914–1932).

The 4 icons around the central circle are part of the Kochchi state
emblem, which clockwise from top left are, palki/ palanquin
representing progress, Shripadmanabha Shanku (conch of Lord
Shripadmanabha) representing enlightment, changalavattam (chained oil
lamp) representing prosperity and chhatra (umbrella) representing
protection and welfare of the state citizens by the government.

The top panel shows the inscription Kochchi Anchal meaning
Kochchi Post, in pre-reformation Kairali script of Malayalam language,
the official state language of Kochchi.

The bottom panel shows the denomination Ett Pai (Eight Pai) in Malayalam.

The 8P denomination was issued to pay the letter postage 8P for weight
between 5.83gm (½ tola) and 11.66gm (1 tola) as well as to pay the 8P
part of the 1A8P letter postage for weight between 58.3gm (5 tola) and
87.45gm (7½ tola), the rate in effect from June 15,1922 to August
16,1932.

Cancelation: It is Pai type 41/Trowbridge type 7a combined
obliterator and date stamp.

This type was exclusively used in just 3 Añchal Offices.

1. Chittur
(10.6772°N 76.7163°E)
Palakkad, Keralam

2. Irinjalakkuda
(10.3447°N 76.2094°E)
Trishshur, Keralam

3. Vadakkancheri
(10.6617°N 76.2363°E)
Trishshur, Keralam

Now, the earliest and latest recorded dates of usage of this type are
as follows.

Chittur
August 17,1945–November 30,1948

Irinjalakkuda
September 21,1925–February 15,1950

Vadakkancheri
January 3,1926–August 25,1949

The postmark shows the date 5 MAK 04 (Makaram 5,1104) in
Kollavarsham calendar, which corresponds to January 22,1929.

So, this stamp must have been used at either Irinjalakkuda or Vadakkancheri AO.

Here is a simplified table of On CGS overprints on Kochchi Ramavarma
XV and Ramavarma XVI stamps.

Thanks Joe I really like all the knowledge on this website.