Welcome,
Question 1: Same Scribus Document, different .pdf choices on export.
General Tab:
For Print - Compression=Lossless, Compression Quality=Maximum
For Web - Compression=Lossy, Compression Quality=Whichever level keeps you under 10mb requirement
Fonts Tab:
For Print - Outline
For Web - Embed/Subset if the fonts allow
Color Tab:
For Print - Output intended=Printer
For Web - Output intended=Screen/Web
Prepress Tab:
For Print Only, if you have questions on this tab please just ask.
Question 2: I would avoid color management unless your printer specifically asks for it. It is not usually necessary in this day and age, especially if printed on digital presses these days.
These are just my suggestions, others might add or subtract.
mnawij