Hi @mariusinbrisbane ,
For your questions:
1) For the 3 data roles. Sorry to say, I'm afraid medyo lagging behind ang AU pag dating sa mga IT specific . and if you will notice walang SOL na specific sa Big Data Role but regardless, you may want to check the individual available occupation and see where most of your JD fits. medyo generic naman ung iba so I think makakahanap ka ng Suitable for your job role.
Getting a visa goes with the same procedure. either 189/190 , but right now they are accepting more on non-offshore applicants.
2) Finding a job naman still vary, iba iba ang kapalaran pag dating sa job finding đŸ™‚ yes what you listed were correct. mainly Seek ang platform. Some of my friends were referrals .
3) I think na answer ko na cya sa item 1
4) I think you have a shot especially kung maganda ang track record mo sa data role mo. not known to many Big data is one of the key tech to digital transformation. ang most companies are undergoing digital transformation stage. ung ibang tech to mention are IoT and Blockchain. So these are niche roles that I think may be boom for sponsorship.