I appreciate that you are worried on our behalf, and even agree that there is precedent of local councillors moving to higher party politics - David Michael was a councillor of Stirling when I worked there, so I know this first-hand.

What you likely won’t know though is the galaxy of differences between Local and State politics in WA:

1. The parties don’t exist at the local level. Councillors certainly have platforms that may be compatible with ALP/LNP/Green policies, but the parties themselves are not represented.
2. Local Elections in WA are not compulsory. You can get elected to a ward with 2,000 votes. Once you get to the state level, everyone votes, and your 2,000 votes are a drop in the ocean.
3. It is extremely difficult to get elected to the Legislative Assembly or Federal Parliament without the support of a party. As awful as that fact is, the vetting process to get preselection will weed out the nutters. You can get a senate seat on a fringe platform, usually with some hilarious preference deals. That’s how Family First became a thing in the first place. A senate seat isn’t going to introduce legislature, though.
4. The article doesn’t mention schools or education, because in Australia this is not handled at the local level. You’re correct in that they have a specific agenda - but neither education nor health is not handled by LGAs. I don’t want to entirely dismiss these people as being unable to do anything too nefarious, but well, I honestly can’t see what real harm they can do.
5. If the majority of a council goes rogue, the minister will step again in as David Templeman did to City of Perth a few years back. Coincidentally, the present LGA minister happens to be David Michael - who knows all about how an LGA should perform.