Lines are non-connected things that you show on the schematic, like borders, titleblocks,stack up notes, etc.  You can just draw them on the schematic, but if you want to save them in a library then the get saved as lines.  You access them with 'Add 2D Line from Library'. 

Do you mean a template sheet that is opened when PADS Logic starts up?  Here is an old note that I have that I believe is still valid.

Logic – Startup File definition

To set the file that opens automatically when Logic is started, you need to export it <File><Export> (select all) and save it as the default file:

C:\Programs\9.1PADS\SDD_HOME\Settings\default.asc

Instructions:

1. Set up what you want for a template design

2. <File><Export>(select *.asc) and save it to:

<SDD_HOME>\Settings\default.asc

3. < File><Export>(select *.txt) and save it to:

<SDD_HOME>\Settings\default.txt

(I don't recall why I had to save both the ASC and TXT files; it may require only one.  Let me know what you figure out)

I believe the only way to add off page symbols is by editing $OSR_SYMS.  You create a special symobl for $OSR_SYMS just like you create any other symbol in the SCH Decal editor.