05 brake accuator failure DIY/help

1. Mini VCI is pretty much a crap shoot as to whether you will get one that will work reliably. Many work good enough to read codes, which is for what most are using them. Better options are Tactrix Openport 2.0 (USA designed and built) or VxDiag Nano for Toyota (Chinese). Be sure that you do not buy a clone or a counterfeit of these products, they are out there.
2. Techstream can be downloaded from the TIS website as part of the $55 for two business days subscription.
3. Can't comment on this, you will need to see if the part number is the same across 2004-2005 and 2006-2009. If it is a different part number, what is the difference. May be the 2006-2009 part (if different) superseded the 2004-2005.

Not sure why people (in general – and this is not specifically directed at the OP) are affronted by having to pay for a diagnostic. Most mechanics would be happy to not charge for it if people then went on to have the repair done in their shop. But the way it has gone is that people started to use mechanics as a free diagnostic service which for some reason a lot of mechanics felt this was taking the p1$$. The resulting push back is charging for the service.

The reality is that mechanics have to feed their children and provide a roof for their families. Even if it takes 15 - 20 minutes to read a car, followed the 20-30 minutes discussion of what is wrong and the options to fix, right there you have 35-50 minutes in direct labor costs – $70 - $100 right there. Then there is the purchase of multi vehicle brand capable scan tools, and ongoing update costs to accommodate new models. Not to mention licensing costs for brand specific IP.

Come on people, $100 - $120 for a diagnostic is not robbery.