You can search using wildcard % eg: Surname: % (tick exact) and Name: Edward with a date range
Birth: 1856 HOLMES, Edward; NULL; Huldah HOLMES; Adelaide; 5/33
Unfort not your Edward as death: 1857# 5/182 HOLMES, Edward; Huldah HOLMES (M); Adelaide
You can also trawl through the alphabet eg: Surname A%, B%, C%, etc. and Name: (left blank) with a date range. These are some examples:
1856 HEINSTER Heinrich Fredrich Stolle; NULL; Dorothea HEINSTER; Onkaparing; 6/40
1857 DEWELL Franklin; NULL; Charlotte DEWELL; Adelaide; 7/10
1857 GASNEY George; NULL; Ellen GASNEY; Adelaide; 11/14
1857 LOGAN Frederick; NULL; Mary Ann LOGAN; Strathalbyn; 13/25
There are others with a lot of “null” which makes things harder.
1852 THOMAS NULL ; (not recorded) THOMAS; NULL; Adelaide; 4/3
1852 NULL August Carl; NULL; NULL; Adelaide; 4/10
1853 NULL NULL; NULL; NULL; Adelaide; 4/163
1854 NULL Hermann Johann Friedrich; NULL; NULL; Adelaide; 5/12
1855 NULL Augustus; NULL; NULL; Adelaide; 5/183
1857 HUTCHINS NULL; NULL; Ann HUTCHINS; Adelaide; 7/19
Also wondering if unmarried mothers simply used their own surname for the fathers details to avoid issues. eg: 1850 MORGAN, NULL; (not recorded) MORGAN; Elizabeth MORGAN; Adelaide; 3/16
Can I use wildcards in the search?
https://www.genealogysa.org.au/help-faqs.html