For #1, you can export specific views. This is the only way I know how to do it, if you choose --fullpdf, it includes all pages.
For #2, I'm not sure, can you post an example? Are you using a custom font?
I was looking to exclude specific pages in my workbook and export many views (18 out of 20) (17 out of 20). This can be done by publishing separate workbooks with different sheets slected and export as required.
The font was not supported on Tableau server but it was supported on client machine.I am getting correct font with render=true but render=false gives incorrect font