I can modify any WordPress theme professionally no matter what the design is. I worked on over 500s of WordPress themes and premium themes. I can work on some points for your website based on the service budget as stated - as points will increase so will the total budget

_ Installing WordPress with your preferred theme
_ Tweak layout or change design
_ Add functionalities like menu/sidebar/widgets/custom pages etc
_ Installing ecommerce plugin
_ populate contents 8-10 pages
_ Install plugins
_ Fix any bug
_ Add/Delete/Replace any block on site
_ SEO optimization by plugin
_ Security check
_ Content Editing