ad 1) You can add your own rows and columns etc.
About Header - you can change style from Template Options - Basic - Header - Predefined Header.
ad 2) ??? I don't know what you expected, but look at my above tip.
ad 3) Hmm, on all my demo sites it works. I can change colors from Preset - Custom Style.
It must be related which the error that you had "Call to undefined method ScssPhp\ScssPhp\Compiler::setOutputStyle(..."
Can you give me Super User account / permissions .
ad 4) Those are social share icons for article view only. It cannot be moved so easy.

But classic social icons from template you can set at the bottom / footer.
I set you already

Social icons in Footer2 (yes, you can move into bottom3 or 2)
