Sorry I have not used the apple products, if you have 3 machines you may want to look at renderpal they offer a 3 node private individual/startup license for free.
with regards to twixtor: revisionfx has 2 types of licenses for twixtor one that use render queue (Interactive AE & watch folders) and the other which is for aerender.exe (cmdline render utility that comes with After effects). Anything that uses the render queue requires a full license, where as the cmdline version was like 65$ USD for non-pro version & ~120$ USD for pro version. With regards to the license only the full version license is OS specific. check here for more details: http://www.revisionfx.com/products/twixtor/pricing/#ae_compatible_4
Hope it helps.
Thanks again! - I have sent some mails to Re:Vision contact centre to weigh up our options. We are still working on the first part of the project, and being self-funded, our budget is a little tight. Honestly, when we go live, and we believe it will be successful.. I would like to get as many plug ins as my little heart desires. I would love all of Video CoPilots stuff, and Red Giant, and Boris, and+and+and!
For now, I am being a little cautious though. So, we need twixtor to make up the extra slow motion our camera cant do, but other than that, as far as After Effects special effects go, we will probably try to use mostly stock footage for the first part. Our greatest "Issue" is going to be rendering time - I will look into your suggestions, as see what we can come up with. I am going to hand over my to IMAC's and get myself two powerhouse PC's instead. The MACS will go back to the the other guys, so we will still use them, just not for now. So all licenses will be PC licenses to start with - untill we make the big time, and hire the entire forum to come work with us!
Take it easy,
and thanks agan for the advice.