I've never really noted which teams play in the first and second divisions of county cricket, and which Aussies play in the teams. Most Aussie cricketers play in Div 2.

There are 8 teams in Div 1 and 10 in Div 2.

Two from each are relegated and promoted each year.

In coaching  a lot has been made of Jason Gillespie's coaching sojourns in county cricket. He is currently coaching in the second division  of 10 teams. His current team ( Sussex?) is down near the bottom of the ladder . He is often discussed as a possible coach for the Australian national teams.

Stuart Law also coaches a team who are higher up in the second division .

Michael Di Venuto ( who trains in the same gym as me when residing In Aus) coaches Surrey who are in the top division and are staying up.

None of our players feature in the top run scorers and wicket takers in either division in 2019. The notable exception is Marnus Labuschagne. He has averaged 65 and has top scored in  Division 2.