Shopify Theme Customisation

I'm looking for support customising a Shopify theme I've purchased.

The majority of the elements I require are already within the theme, they just need adding to certain pages and tweaked slightly. I have sketches of my preferred layout, references from other websites and am happy to discuss on a call if easier.

The main changes are as follows:

- Adding Header to each page, formatting to have the brand name in the centre and 4 small icons - Burger, Search, Account and Cart - 2 in the left corner, 2 on the right (See Header Reference 1)
- Adding search functionality from the header, not needing to click through into a separate page
- Ensuring the Burger remains top left in the header across all pages - desktop and mobile
- Ensuring the background colour of the quantity box on the cart page matches the colour of the rest of the page (See Cart Current - 1 & Cart Reference - 1)
- Removal of the "Back Home" button from the Products and Collections pages (See Collections Current 1)
- Stacking of the images on the Product pages to allow user to scroll through images (see Product Page reference 1-3 & Current 1)
- Rename "Keep Shopping" button to "Back to All"
- Add title to "All Products" Collection Page (See Collections Current 1)

See link for reference images - https://drive.google.com/drive/folders/1slpH_XgoDnPQFQQaIdO6OccHq5l4qaRg?usp=sharing