1/.Front page:
you are using porto theme, i have to edit theme files to fix your problem but if i do that ,when you update your theme my work can be gone. So i will create a child theme, and make modifications on this file, so even theme updated, my work will stay.
2/. Category Page:
i dont remember porto category page stracture well, so i have to check it first to tell you how i will fix it but i can do.
4/. Advice & Instruction on how to change the colour scheme of the theme.
some of them are from admin panel, some of them from css files. can you give more details about ehat kind of changes do you eant?
i am 39 years old , working as programmer and developer over 18+ years and using magento since ver1.6. if you look my profile you see that all my clients say "fast work" with 5 star.