I think its better to keep this thread to @Leo's script (having two conversions can get confusing). Sounds like you almost have it sorted anyway.
If you want to persist with the Style Setter script, would you mind posting in that thread?
To answer your questions though.
Issue #1 Is resolvable a couple of ways. I will update scripts main post to detail how to do this.
Issue #2 As the script is just changing Styles I think this should be fixable. It should just use your default settings. I don't think it does that for me.