Hi Tyko,
The audiosnap markers in your project might have accumulated or got corrupt perhaps which could explain the problem with bounce. A quick way to rid a project of audiosnap markers that were unintentional is to turn off audiosnap as suggested but also to save the project as a bundle file and load it back. When you save as a bundle you will get a prompt that proceeding will remove audio snap. If you choose OK it will save the file without audiosnap markers so when you load back it will be removed.
Regarding your automation question there are two ways to globally raise automation levels on a track. One is using the automation shelf tool - with the smart tool hover the mouse on the top area of the clip and when the cursor changes to the shelf tool drag and you can change all nodes on the envelope at once.
The second is using offset mode which is ideal when you want to preserve envelopes on a track/bus but apply a static gainstage from a fader on top of that envelope. This is a very powerful and relatively underused SONAR exclusive feature. When in offset mode each fader acts as an additional gainstage compounded on top of the envelope gain and is very useful when you want to make global adjustments to a track/bus. I use it all the time in my mixes.
PS: very nice work on your guitars. I liked the tennis racket design too :)