Dear,

1. for change image slider https://www.themepunch.com/revslider-doc/main-background/

    for change button slider https://www.themepunch.com/revslider-doc/buttons/

2. for change footer content: you can goto backend -> widget -> edit footer widget

3. I see you changed 

4. If you want customize header, You can use child-theme and create folder inc/template-parts/headers, coppy files in parent theme headers folder into child-theme header folder and edit its.

5. If you have any question you can create ticket.

6. All shortcode of theme in plugin tinos-shortcodes.

Thank you!

Yes,

You able to separate the teams. Please try and feedback. Thanks.

Dear,

If you want show 2 to 5, you must enter "show item" is 3 and "From Item" is 2.

Please try.