To be perfectly honest with you, I have never updated either Flash or Air in all the versions and years Poser has been using them.  Back in the P8 days, SMS tech support told me to disable the auto updates.  They told me that the version of Flash or Air is adequate for the Poser's needs.  Since I have no real need for Flash or Air outside of the Poser library, I have all versions of Poser from P5 to Game Dev on my system.  This includes all the Pro versions.  Never updated Flash or Air.  Never had a problem. 

So, if the only thing Mac users need Flash or Air for is Poser, why not install the version that is part of Poser and let it go at that?

I'm not entirely sure where you would get the SM flash version. When I installed poser on this new mac a couple of weeks ago, I was forced to go directly to adobe in order to use it. And now, once again just 2 or 3 weeks later. So, maybe it was installed but it was being blocked by apple. I have the same problem with Java. I have an IDE that I use that requires Java, and that version was blocked, so I had to go to oracle and download the latest version of the JVM.  Oh well. Maybe I'm the only one who finds this really annoying. 

As for anti-virus, I have been using the mac for nearly 10 years, and I have never installed anti-virus nor have I had any problems. Part of it is that there isn't as much to gain by exploiting macs (fewer numbers), but I think the general security model for unix was very mature when script kiddies started exploiting windows back in the late 90s, making anti-virus necessary. All you needed to know back then was basic, and you could write yourself a melissa virus that took down whole companies for days.